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Trailing arm bolts

Posted: Wed Jan 04, 2017 11:43 am
by SprintMWU773V
I've always wondered whether the trailing arm bolts where they go through the body should have a washer fitted. Parts book and my memory suggest no but wondered whether it would make sense to fit one to prevent the bolt head burrowing into the body mounting?

I'm removing my temporary axle this evening and will then move onto fitting the refurbished one.

Re: Trailing arm bolts

Posted: Wed Jan 04, 2017 12:37 pm
by tony g
I fit one both sides as it stops the paint/powder coat getting squashed and flaking.

Tony

Re: Trailing arm bolts

Posted: Wed Jan 04, 2017 8:15 pm
by Flyfisherman
Mark

Fitted one under the bolt head & other under the nyloc nut

Paul

Re: Trailing arm bolts

Posted: Thu Jan 05, 2017 8:53 am
by trackerjack
Fit them, because there is no reason why you should trust BL to have got it right in the first place.
My TR5 (wish I did not sell it!) front suspension sat on a little welded steel box on the chassis and these are now well known failure points on TR5&6 and my cure at the time (before it was a well known fail point) was to fit a large washer to spread the load and as I competed in many speed events and the car was sold on to a friend who competed and won the post historic national championship in it with no suspension fail, I guess it was better than the penny pinching BL effort that would fail sat on your drive without any extreme race track test.
Remember that a bean counter working in a company like BL saw a dozen washers at a penny each as a great saving! so overruled an engineer who would recommend them to be fitted.

Re: Trailing arm bolts

Posted: Thu Jan 05, 2017 8:54 am
by trackerjack
Fit them, because there is no reason why you should trust BL to have got it right in the first place.
My TR5 (wish I did not sell it!) front suspension sat on a little welded steel box on the chassis and these are now well known failure points on TR5&6 and my cure at the time (before it was a well known fail point) was to fit a large washer to spread the load and as I competed in many speed events and the car was sold on to a friend who competed and won the post historic national championship in it with no suspension fail, I guess it was better than the penny pinching BL effort that would fail sat on your drive without any extreme race track test.
Remember that a bean counter working in a company like BL saw a dozen washers at a penny each as a great saving! so overruled an engineer who would recommend them to be fitted.

Re: Trailing arm bolts

Posted: Thu Jan 05, 2017 10:38 am
by SprintMWU773V
Thought as much. It doesn't seem like good engineering to not fit them but thought it was worth canvassing opinion. Just need to check stocks of suitable washers for the arms and the tie bars.

I undid the temporary assembly last night including the shocks into the trailing arms so it's now ready to lower down later on. The shock bolts were particularly corroded but I think it will be easier to lower down with the rusty old ones still in place in case they fall and drag across my nice paint!

Re: Trailing arm bolts

Posted: Thu Jan 05, 2017 11:24 am
by Magenta Auto Sprint
I too have added washers where I believe they should be used, as mentioned good engineering practice for spreading the load etc but also this stops the hex heads from deforming metal and forming stress raisers.

Also good eng practice is to have at least 2 complete threads protruding beyond any nut. I have noticed that the BL bean counters have made their own length of bolts in many cases.

I have found original bolts that are 1 3/8 long, so when you buy new bolts, an 1.500 is too long and 1.250 is too short.

Malc

Re: Trailing arm bolts

Posted: Fri Jan 06, 2017 7:47 am
by Toledo Man
There are some good points made in this thread. As Jon has said, BL didn't always get it right first time and the extra length of new bolts will allow for the thicknness of the flat washers to spread the load.

Re: Trailing arm bolts

Posted: Fri Jan 06, 2017 9:05 am
by SprintMWU773V
Old temporary axle removed! First major progress since my move. Wasn't the easiest thing to do but got there in the end.

The one I removed, which is rather unknown is now available for FREE to someone who wants it - viewtopic.php?f=11&t=32094

Re: Trailing arm bolts

Posted: Fri Jan 06, 2017 10:26 am
by PollyB
Keep going Mark, would love to see it on the road.
Are you going to be ready for the first Tatton? Eric is collecting names.

Re: Trailing arm bolts

Posted: Fri Jan 06, 2017 10:31 am
by SprintMWU773V
No it won't be ready for Tatton, not this year anyway. One little step at a time for me at the moment.