The e34 rear sill thread

[FIVE-OH 152]

With the long winter nights well and truly upon us and with a bit of free time, I've decided to finally do a full thread on how I completed a rear full sill repair on my e34. I've had communication with various members looking for advice and I know there are a few forthcoming repair/restorations imminent. The purpose of this thread is to primarily help those about to go through such a task.

 

 

With even the last e34's now approaching 25yrs old the one issue that dominates longevity is unfortunately corrosion. Although superbly designed, the e34 does still have areas that are vulnerable to rust with the sills, especially the rear, high on the list of common areas. Bearing in mind that the e34 5 series was possibly the last BMW to be built to traditional methods, it's the sills that contribute to the core strength of the chassis.

 

I will say that although I can weld, I'm not a fully fledged 'body man' so to speak. My method of repair may be considered long winded, but it did ensure all traces of corrosion were eradicated. 

 

Here's a shot of the car just prior to the repair commencing.

 

 

Not bad looking you might think....

 

So here goes...

 

2015

 

During the annual MOT the previous year the tester had remarked 'I'll give it to you this time, but next year, no chance!' in regards to the rear sills. So early in the summer I began to assemble what I thought I would require to complete the job, namely a pair of klokkerholm repair sills and some mild sheet steel. By mid summer I started on the car, naively estimating completion within 6-8wks......

 

 

 

As can be seen, the corrosion is obviously well established. Time to start cutting....

 

 

 

The first of well over a hundred spot welds to be drilled out. 

 

 

 

The real truth......

 

 

 

 

 

In the words of my friend on here Geoff (dongiov) when he had a similar experience...Ewww

 

 

I knew it had rust, but at this level? To cut a long story short I spent the next few weeks attempting to make up a few repair sections but imo I failed. Towards the autumn I parked the car and began to ponder what to do with it. I realised early on that the klokkerholm sill panels whilst excellent in quality were not going to be suitable to complete the repair. Also it was clear the inner sills were rotten as well as the floor pan adjacent to the rear seat heel board. Great.

 

Not only that! After a thorough inspection of the complete car, i finally realised that all four corners had serious corrosion at and around the jacking points, the wing bottoms had also rotted out, as well as a few areas needing attention.

 

Devastated was an understatement. 

 

I parked the car up and abandoned it.....

 

 

2016

 

Not a great deal happened during the year. With a major house project and a child off to uni, it didn't leave much time or money for messing about with old BMW's,  2016 was in effect a wash out. It was the closest I came to giving up and scrapping it. But after 14yrs ownership I just couldn't quite bring myself to do that.

 

The real work would began 2017.

 

I don't particularly like the cold so from early November to late Feb it's rare to find me doing my own stuff unless strictly necessary. Although I have a double garage with ample hard standing at home, I wasn't in a position to do the work there. My place of employment was used instead but that meant the car had to be parked outside everytime I worked on it mostly during the evenings. Taking it in and out each time was a royal pita though. Would have been completed much faster otherwise.

 

 

All comments are welcome. Look out for the next instalment in this mission soon.

[duncan-uk 2,768]

I think i would have cried seeing that!

 

I do wonder how long my e28 would have lasted before needing surgery. Despite looking great when i broke it there were definitely areas heading down hill..

[Hogie 42]

Nice read, mine was nearly exactly the same as that.....although I had to outsource the skill required to repair it.

 

 

[Flandy 94]

I look forward to the next installment!

 

Discovering more rust than you expected is never fun, and when it's an area like this where several awkwardly shaped panels meet like this, it can be a nightmare to remove all affected areas properly, and as bad or worse t stitch in the new panels. Respect for sticking with it. 

 

Mine needs the bottom of the drivers front wing repairing, and a bit on the floor/inner sill in the drivers footwell, I've no doubt when the sill trims are removed I'll find something at the back of the sills, but the signs are reasonable that its pretty localised, and the jacking points aren't too crunchy (unlike my E39's rear jacking points, which are both buggered!). I've done the front and back of the sills on my E21, whish wasn't fun.  I must like welding, or I'm stupid, not sure which..........

[Azmontana 116]

I’ve been doing my sills all round too. Fronts were bad. Rear weren’t as bad. 

[FIVE-OH 152]

Towards the end of 2016 I began to try and source the required panels for the repair. New for all realistically was out of the question. The outer sill/wheel arch, inner sill, lower inner wheel arch, and a section of floor were all required, 

 

So after a few weeks looking in various breakers yards and dismantlers with no success, by chance I came across a late model 525 in Hemel Hempstead, just in, complete and fairly clean. It had apparently failed its annual MOT and whoever owned it just couldn't be bothered with it any longer.  I unfortunately missed this car by a matter of a few hours. By the time I seen it, it was already doomed, having been bought to be stripped of engine and g'box, all it's running gear, opening panels and wings to be shipped to Eastern Europe. I would have happily smoked around in it had I got to it in time. High mileage but plenty of life in it. A bit of a shame.

 

 

 

 

 

 

 

After a thorough inspection of the rear sills and finding them to be in exceptionally good condition, I arranged with the staff to have them cut out completely. I'll admit. I moaned when quoted £85 for the pair but in the end it was money more than well spent. Also, to be fair to them, with the time and effort it would have taken, plus the gas used, the quoted price was more than fair. 

 

I immediately began to unstitch the welds to salvage what was needed. One side was pretty much perfect but the other did have some corrosion that did require repair.... Without these inner sections the job would have become unviable on grounds of cost imo. Also only one side inner sill was available from BMW at the time. Nowadays, both sides are NLA.

 

 

 

I had started on the o/s but and I'll come back to that side later ..

 

Now the real work begins 

 

 

First cut.

 

 

Same story....

 

 

 

 

Seen clearly here is the drain tube for the sunroof. Too short in length imo. Should go down to the very bottom of the sill to channel water straight out of the drains.

 

 

Heavy rot on floor section.

 

 

More cutting..   plenty more of this forthcoming.

 

 

Rear section of inner sill and rear inner lower wheel arch fully exposed. The 'brown' areas speak for themselves..

 

 

Heavily corroded floor section. Completely rotten. Mounting for rear brackets about to give way. This area is behind the inner sill.

 

 

 

 

 

That little spot of rust...

 

 

...Turned out to be much more deep seated...

 

 

Here, the majority of rot has been cut out, though it still looks awful. It's basically all sound steel.

 

 

Same location after a thorough cleaning up with a knot wheel. 

 

 

The n/s/r corner was by far the hardest to tackle. All the wiring inside the car in the vicinity of the repair needed to be moved due to the risk of burning and to provide additional access. The external fuel pipes also should be removed, but I got round that by covering them with some aluminium plating and being very careful. I used bilt hambers excellent electrox zinc rich primer to coat. 

 

I purchased the superb (imo) OEM BMW rear outer sill/wheelarch sections  part# 41 00 8181 707/8.   Readily available if a little pricey.

 

So far I'd only been cutting. In the next part I will be preparing the salvaged inner panels and welding them into position. 

 

More soon.

[duncan-uk 2,768]

Recognize the breakers, not been there in a while but they where always pretty decent and it was a proper yard where you could have a wander and a rummage.

 

Back in the day they had a couple of nice e28's but got things dumped on the roof

[FIVE-OH 152]

So to continue.

 

With all rot now cut out it was time to start reconstructing. All salvaged pieces were fettled and tidied though I did have to make some minor repairs.

 

 

Rear floor section. Note profile shape.

 

I wasn't happy with the salvaged section of inner wheelarch so repaired that. Luckily, I was able to retain the profile of the  section so a fairly straightforward repair.

 

Poor section cut out....

 

Repaired and partially cleaned off.

 

 

 

Also a small repair to the inner sill itself 

 

 

 

 

 

 

...and cleaned off.

 

 

With that done, it was time to start building up 

 

 

 

 

 

 

 

Floor section installed.....

 

Then onto.....

 

...Rear wheelhouse lower repair section. This piece/area is usually damaged due to incorrect jack placement when lifting the car.

 

 

And welded..

 

 

 

Then the repaired, rear inner wheel arch lower section clamped in place and cut.

 

 

 

 

 

Tacked....

 

 

And welded.

 

 

 

 

 

Rear suspension bracket fitted in place to double check fitment. All lined up perfectly.

 

[FIVE-OH 152]

Pressing on....

 

Firstly an interesting shot.

 

 

The three panels that join to form the bottom seam of the sills. From L to R, outer sill, inner sill, floor pan. Very strong method of construction. The gap to the right of centre to be filled in later.

 

Anyways... A few weeks later it's time to fit the inner sill.

 

Here's what it looks like (and unfortunately NLA both sides)

 

 

 

Firstly all required spot welds drilled..

 

 

 

And inner sill removed. Note stiffener bracket now in place. The two 13mm bolts for the forward suspension braces bolt in here.

 

 

 

Plenty of BH S50...

 

 

 

With the car on its wheels, the inner sill is tacked into position...

 

 

 

...and fully welded...

 

 

 

..and covered off for the time being in BH electrox.

 

 

 

I decided to leave the outer sill fitment to the very last. With the rear sills now 90% complete, I moved on to the N/S front....

 

 

 

 

Says it all....

 

I decided to repair the original wing. Original wings always seem to fit better than repro items and they only tend to rot at the lower sill section. I had cleaned up this area some 8yrs previously but as can be seen, it was now heavily corroded. I had a old spare wing hanging about that was a pattern and a bit scruffy, but solid. So got to work.

 

The lower section as usual was completely gone. Only the under seal was holding it together....

 

 

 

Here it's cut, joined and tacked...

 

 

 

...Welded and partially cleaned off. A small skim of filler would be to finish if necessary. However the trim disguises any anomaly.

 

 

So that was the wing done. Plenty more to do.

 

Next time we get deep into e34 front sills and floor repairs.

[duncan-uk 2,768]

Very envious of the work shops some of you have!

[simufly 22]

You dont want a job do you?????

[FIVE-OH 152]

So, movin on to the n/s/f sill section.....

 

 

 

From the outside it was obvious remedial work was necessary.....

 

 

 

...But from the inside it was clear the rot was extensive. Note the 3/8th extension pushed through from the outside, at the top of the image. Also the actual floor itself had been distorted upwards, again due to incorrect use of a trolley jack way back in the distant past.

 

 

View from underneath. What's left of the three drain exits are visible, but clogged with debris.

 

 

 

Here's the view after the first cut. Inner sill gone, dummy floor damaged. However, the cut section first removed was basically sound, only needing a good cleaning off and was suitable for reuse.

 

 

 

Here, I've removed the dummy floor.....

 

 

 

 

.....and a portion more of the outer sill, revealing the heavily corroded jacking point strengthener.

 

 

Another image of the problem area from inside after a little clearing.....

 

 

..and after the rot has been cut out..

 

 

..and with a simple right angled repair plate welded into position. The floor itself was reshaped back to it's original shape

 

 

Here, the first of two inner sill repair sections is tacked into place. Jack strengthener now removed.

 

 

 

 2nd section marked and shaped..

 

 

..clamped and tacked..

 

 

..and welded. I was a bit pissed off with the whole job by now and it shows with me being lazy and not shaping the rear section correctly and having to infill that small triangular section at the top.

 

I was using a fairly powerful, but old machine that unfortunately was quite temperamental throughout the job. At times it would run perfectly but at others it could be a real pain. Settings-wise, I tended weld on the minimum setting with a suitable wire speed for the material being welded, i.e. 1.0mm sheet steel,  but still had to go slow to avoid blowing through.

 

 

Now a view from the rear. I actually made a major mistake here and had to modify it later on. I did not allow for enough depth. Not bad welding penetration if I can say so myself.

 

 

 

A word on the jacking point strengtheners. They are not the same front to rear, so some improvisation may be need. Over time I had collected a few rear strengtheners so cutting a few up got me a repaired piece I could use.

 

A bit of jiggery pokery.. 

 

 

Eventually got me this.

 

 

 

Heres the area after cleaning off, just prior to replacing the jacking point. Note the three cut outs for the water drains.

 

 

 

Reusing the outer section, the forward most section of the sill was formed...

 

 

 

I had already decided to use the klokkerholm sills (I had previously purchased) for the outer repair, so this was cut to shape...wing refitted to check for fit, etc.  A tiny bit of fettling was required to get the wing to sit just right.

 

 

 

Repaired jacking point welded into position and cleaned off.

 

 

 

Fully primed....

 

 

 

More BH s80 applied.....

 

 

 

Outer section welded into place. The bottom of the jacking point must contact the top of the horizontal section of the repair piece.

 

 

 

Even more s80 applied liberally. The shape of the klokkerholm section meant I modified my original closing panel.

 

 

 

Original outer forward section welded back into position..

 

 

 

Revised fabricated closing piece....

 

 

 

...goes in here to close off...

 

 

 

..and fully cleaned off and primed.

 

 

 

From the rear. My previous mistake rectified. The two cut outs are for the spire clips for the lower wing mountings. I'd advise additional sealant to be added here when completed.

 

 

 

Finally a small repair to the dummy floor. Wasn't at all happy with it's condition, so repaired. I believe both sides dummy floors are still available new from your local dealer.

 

 

 

 

 

 

 

 

And refitted.

 

 

 

Job jobbed on this corner.

 

Next time we tackle the o/s and very necessary, extensive floor repairs.

 

[Bumbaclut 629]

lovely work there, wish I could weld/fabricate   

[Sir Anthony Regents-Park 822]

Me too.

 

Nice to see the recycled 525i panels still going. That was 10 years ago! The most utterly mint, 50k from new K plate 525i in Lazerblau - or was it Royal - weighed in of scrappage in 2009. 

[FIVE-OH 152]

On 15/04/2020 at 11:55, Sir Anthony Regents-Park said:

Me too.

 

Nice to see the recycled 525i panels still going. That was 10 years ago! The most utterly mint, 50k from new K plate 525i in Lazerblau - or was it Royal - weighed in of scrappage in 2009. 

 

Well over 10yrs now sir, and for sure they were mint. At the time I hadn't considered a full panel change, but after speaking to you it just made sense. I think in total it cost me £250 all in, including the cost of van hire and fuel, which iirc was approximately £100 of that!

 

I was very surprised when you confirmed the car was lazerblau. It is a rare colour on e34, royal and orient blues being far more popular. I think I've only seen perhaps five or six lazer examples in the flesh, other than my own example. 

 

Here's the only shot I have of the car/victim. I'd hate to think what it would be worth today. A lovely motor and a real shame. I believe you reckoned that at least 10-15 e34's benefited from the demise of this one car.

 

 

And my my own car after the swap.  Probably at it's peak condition in my ownership at this point.

 

 

 

 

Edited May 8 by FIVE-OH

[FIVE-OH 152]

Time to continue....

 

Someone asked me if I enjoyed 'all that welding'. Well it can be pain as some of you know, but tbf it made a change from the usual day job. Luckily I was in a position that if it got too much, I could walk away from it and leave it be. I learnt so much from the experience, and gained so much more confidence that other projects I have that I would more than likely have sub'd out, I will now do myself.

 

The only real negative is the time factor. It takes long to do a good job imo. One of the reasons welding and car restorations in general cost so much.

 

Anyways..

 

 

It was clear that there was a serious problem when I attempted to remove the throttle pedal and it came off in my hand!

 

 

 

After pulling back the carpet all was revealed..

 

 

 

The outside didn't give me cause for any optimism....or an easy job.

 

 

 

From the other side 

 

 

Work cut out then.....

 

 

 

Firstly the dummy floor was unstitched and removed. The rust patch to the right was also fully exposed at this point. Tbf it had been there for years but it had to go. We'll leave that to later, along with the pedal mount and other small items.

 

 

With the dummy floor removed the extent of the rot was fully exposed. Not the end of the world but an inconvenience nevertheless.

 

 

 

After a few days, with everything dried out and cleaned up to assess the damage and plan the way forward . There is barely any connection between the floorpan and sill.

 

I decided to cut the floor out first then build the inner sill up and then fab and fit a new floor section.

 

 

Here I've cut out the required areas ready for a repair section. Jeez that sill was rotten...

 

 

 

In the meantime I started on the sill repair. Again this section was still fairly sound requiring only a good grinding back to bright and capable of being reused.

 

 

After some heavy cutting.....

 

 

Everything was heavily corroded including the lifting point. By far worse then the n/s. The drain tube is clearly visible in the centre of the image.

 

 

 

Note the the profile of the jacking point. Couldn't salvage it unfortunately.

 

With the majority of corrosion removed it was time to start fabricating....

 

More soon.

[duncan-uk 2,768]

14 minutes ago, FIVE-OH said:

Someone asked me if I enjoyed 'all that welding'. Well it can be pain as some of you know, but tbf it made a change from the usual day job. Luckily I was in a position that if it got too much, I could walk away from it and leave it be. I learnt so much from the experience, and gained so much more confidence that other projects I have that I would more than likely have sub'd out, I will now do myself.

 

The only real negative is the time factor. It takes long to do a good job imo. One of the reasons welding and car restorations in general cost so much.

 

I think that's the crux of it, you do it because you want too rather than have too (yes it needed doing but wasn't going to stop your life if you didn't)

 

I used to hate fixing a problem that meant i couldn't use the car for work but tinkering because i wanted too is so much more pleasurable.

[FIVE-OH 152]

Pressing on. Much more than a glimmer of light at the end of the tunnel, as they say...

 

With most of the rot gone...

 

 

..... I started fabricating pieces...

 

 

...firstly the floorpan repair section...

 

 

 

...Then the Inner sill shaped and tacked...

 

 

 

....while outer sill section was also cut to shape.

 

 

 

Floor repair tacked into position.....

 

 

 

...Followed by starting to fully weld inner repair...

 

 

 

...followed immediately by fully welding the floor.

 

 

 

Inner sill repair completed. Just now to clean it off.

 

 

 

 

My solution for the jacking point was to majorly modify a rear strengthener. Not quite original but let's face it, who sees it once closed up?  I did have to add the two little legs to allow full contact with the outer sill section....

 

 

 

...that was fitted next. 

 

More soon.

 

[Flandy 94]

Looking good! It's nice to see this being fixed. I think too many people break cars for rust like this, and while I understand if you're paying to have it fixed, it's probably uneconomical, when you're doing it yourself, the costs aren't that great, unless you start needing expensive genuine body parts. I kno wwhen I've done this in the past, I've always been irritated that I need to do it, and it can be disheartening when you start digging and finding more than you bargained for, but when you start cutting back to fresh metal, and your repair sections take shape, and fit well, it's really satisfying. 

[Sir Anthony Regents-Park 822]

22 hours ago, FIVE-OH said:

 

Well over 10yrs now sir, and for sure they were mint. At the time I hadn't considered a full panel change, but after speaking to you it just made sense. I think in total it cost me £250 all in, including the cost of van hire and fuel, which iirc was approximately £100 of that!

 

I was very surprised when you confirmed the car was lazerblau. It is a rare colour on e34, royal and orient blues being far more popular. I think I've only seen perhaps five or six lazer examples in the flesh, other than my own example. 

 

Here's the only shot I have of the car/victim. I'd hate to think what it would be worth today. A lovely motor and a real shame. I believe you reckoned that at least 10-15 e34's benefited from the demise of this one car.

 

 

And my my own car after the swap.  Probably at it's peak condition in my ownership at this point.

 

 

 

 

 

K974EYL had done 88k, not 50. Even so. I don't think it had ever seen rain and it only did 2000 miles a year. Criminal. 

[FIVE-OH 152]

A bit more...

 

At this point, I started to sort out various minor issues related to the resto.  First up was that nasty patch of rust on the o/s inner wing/rail.

 

After cleaning off the surrounding under seal I was left with this...

 

 

 

All corrosion was duly cut out. Turned out to be fairly localised.

 

 

 

Then a simple repair piece was shaped....after consulting the other side of the car for guidance...

 

 

 

But before welding it in, the inside of the rail was cleaned up as best as possible and then coated with more s80

 

 

 

Then welded...

 

 

 

Followed by another piece to cover..

 

 

 

Completed, if a little untidy.

 

 

 

..and sealed.

 

 

 

That sorted it was time for the T pedal mount.

 

So starting with a piece of 3mm plate...initially I thought it not entirely suitable due to it having a chunk missing out of it, but it was the only piece I could find. Ultimately it worked out well.

 

 

 

After a bout in the press I was left with this...

 

 

 

....and after a bit of cutting and grinding...

 

 

 

...It was tacked...

 

 

 

And fully welded...

 

 

 

After cleaning off, the left leg was repositioned to corresponded with the step in the floorpan. Experienced welders will spot immediately the minor mistake/oversight to this particular weld.

 

 

 

The completed article.

 

 

More soon

[FIVE-OH 152]

The dummy floor was quite poor in places. This part appears to be still available new from BMW. Not sure on cost, but knowing them....

 

Anyways, a couple of hours saw this item suitable for reuse.

 

Firstly a simple repair section was let in on the sill side of the panel at the rear corner. Here it's tacked...

 

 

 

Then fully welded. To save time the excess was trimmed off after welding. Usually I'd cut to shape first then weld in.

 

 

 

This was followed by a slightly more tricky repair to the forward section, again on the sill side. Repair piece made up first..

 

 

 

...welded and completed.

 

 

 

Finally I needed to do something about the floorpan drain hole bungs. Thankfully simple affairs on the e34 platform.

 

Not being sure how to approach the issue, I started to look around the workshop, finding an oil seal installation tool that had a useful depression in the head and appeared to have the correct diameter. After cutting a circular piece of steel and placing it on the tool, a socket was used with the press to form the required shape. Whilst in this position the exposed edges of the disc were tapped flush and level with a small toffee hammer and finished off on the bench grinder.

 

 

 

 

The final result. These were bonded to the shell rather than welded when being manufactured on the production line. In the end though I only needed to make the one.

 

 

Must admit. I was fairly pleased with the end result.

 

I also wasn't happy with some areas of repairs to the floor so rectified. This area was full of pinholes as was the general repair to the floorpan. Took a fair amount of time going over it again to sort it properly but the area around the drain proved to be thin so cut out and replaced also.

 

 

 

 

 

 

 

Ready to clean off.

 

Next time we'll complete the repair to the outer sill.