Jump to content

outer lower fulcrum bolt torque


Recommended Posts

Dear colleagues, I have completed the change of lower inner suspension arm bushings. When reassembling, I have not been able to find the torque setting for the bolt that acts as the lower outer fulcrum. I have both Haynes and Bentley manuals, but they refer to Section 4 and there you only have the reference to the TR4 and earlier system, where the trunnion had two studs, rather than the tr4a system with a single bolt. The manual indicates 5 lb ft (which seems low), and a certain play. But then, the TR6 manual, the TR6 having a similar arrangement to the TR4 (with a Through bolt and a single castellated nut), indicates 50 lb ft... I have seen this question.in this and other forums, with no clear answer. Your views would be much appreciated.

Link to post
Share on other sites

Hi Enrique,

 

on TR4 it must be softly tight an than slack again 1/6 - 2/6 turn, on TR4A tight because of its different construction.

I use on my TR4A no special torque, just reasonable tight.

 

BUT therefor the steel bush #93 must me a minimum longer the the pressed in POM bushes #94,

AND the washers #95 must be of harded steel and must not be of zinc coated tin.

See this broken harded on, a tin washer you can bend.

 

A tin one can not stand the preasure of the steel bush and will "melt" away.

 

 

 

Ciao &:-) Marco

Edited by Z320
Link to post
Share on other sites

Hi, Marco. The bushings are Nylatron (presumably fitted by prior owner and you can see the steel tube in the inside. The washers and very thin (they look like they are designed to slide on the nylatron), but they are, indeed, steel. I agree with you that the 5 lb ft torque seems to be OK for the TR 3, but the TR4A assembly looks like it needs more torque

Link to post
Share on other sites

By the way, just when I thought I was done, I saw that the inner nuts of the spring pan were not tight enough (the washer could move). Upon closer inspection and after undoing some of the hard work I had done to assemble the suspension, I realized that a previous owner had fitted the studs the wrong way in. I managed to take one out and insert it correctly, but the other one was stuck, so I ended up putting three washers...

Link to post
Share on other sites

Hi Enrique, it's all a bit tricky getting the 4A to 6 lower trunnions right, you have to have the through bolt tight enough to prevent the brass trunnion from revolving on the through bolt, this is achieved by locking the spacers 93 to the trunnion with sufficient torque from the through bolt, this means that the trunnion, bolt and spacers move as one rotating on the bushes 94. This is all dependant on all the spacers, thrust washer, seals etc having been made within tolerance, too small and the trunnion rotates on the bolt, too big and everything locks up.

Cheers Rob

Link to post
Share on other sites

Hi, Roger... too late, I am afraid... I must say, though, that I never felt the suspension being too hard (at least with the old (shot) inner lower bushings... let's see how it goes... BTW, getting the spring pan aligned with the lower arms is a pain in certain part... I was lucky the first time, but then I had to undo to insert the inner studs correctly (see above, only 50% successful, but I managed to sort it out putting three washers) and the 2nd time it took a lot of time and forceful but careful persuasion with levers and plastic face hammer

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.