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stevenc3828

Failed dogbone links - warning aka pitman arms

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Bought a pair of pitman links / 'dogbones' / stabiliser links in April. Cheapest ones on eBay to get the daily through the mot. Installed as per the BMW manual online

 

I know the old saying about buying cheap but I didn't expect them to have failed in less than 4 months so probably best to avoid Aurecom RP3463 until the quality improves. Other reference numbers are QLS3002S, FDL6199, and SS021 plus OEM reference 33321123463

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Edited by stevenc3828

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Lots of tat/copies on ebay and like you mentioned "cheap". Stick with Febi, Lemforder etc. and you won't go wrong from my experience.

 

If it looks too good to be true it generally is.

 

C.

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Dogbones were the very first thing I changed on my car when I got it, I bought them from GSF and only replaced one a few months ago because it was squeaking but I have done nearly 50k miles since then and I've had my car 4 years now.

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Just in case it is needed, the washers go in between the link and the carrier / trailing arm

E34_Rear_Pitman_Link_washer_order.jpg

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Can I ask where you put the washers on the "dogbones" and how you tightened up the bolts. Both of these are important to correct fitting.

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Indeed

 

As per above re washers and torqued up as per instructions. Wheels on the ground, correct tyre pressures etc, etc

 

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The reason I asked the question is that recently I looked at that diagram when looking for specs for the e34 M5 rear axle. I thought that people looking at it could easily assume that the washers fitted above the "dogbone"

Then I saw your thread and you had made that assumption. The line drawing is misleading. If you look at it you will see a line going through from the bolt to the trailing arm. This sequence is correct. The other bolt does not have a line. The washer goes above the crossmember and then the nut as in a conventional attachment.

I predate the "dogbone". Early BMW's semi trailing arm suspension did not have it.

The problem with semi trailing arm is that when the wheel is raised up on cornering there is a change in track width, camber increases and the wheel can "toe out". This made the cars tail happy as the tendency of the wheel to go straight on in a corner so classic over steer.

The solution BMW had to tame this in the early eighties was the track link or pitman arm or "dogbone". It limits the pivot axis and reduces the effects of toe out on cornering. I would have read about it in the likes of Auto Car or Motor Magazine. (No internet then )

From your other thread you seem to want to install the parts as BMW intended. The way that your car and the earlier 5,6 and 7 left the factory was with the washer fitted between the "dogbone" and the boss on the trailing arm. The other washer goes above the crossmember and then the nut.

https://www.exx.se/maintenance/dogbones/index.shtml

This guy has some pictures showing the correct layout.

 

If you look at the image from the BMW etk the layout is also incorrect. If you google BMW e28 dogbone replacement you will see that some people followed the etk and put the washers underneath as in the diagram.

There is also the idea of fitting them the right way up. The later parts like yours have a "flat" side and a tapered side. The original part did not have that. There is very little in any workshop manuals about it. 

 

To tighten the bolts put the car in what BMW describe as normal position. From memory that is 

68kg on each front seat 

68kg in the centre of the rear seat

20kg in the boot

and a full tank of fuel 

So if you are not doing that then you are not doing it correctly. (Pay a dealer and see if they do it!!)

.

 

Trailing arm.png

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