Printable Version | Subscribe | Add to Favourites
New Topic New Reply
Author: Subject: Suspension Bolts - from the Horse's Mouth!
Hugh Jarce

posted on 18/10/04 at 04:21 AM Reply With Quote
Suspension Bolts - from the Horse's Mouth!

I was just looking at the "Mojo" thread and followed a link to the Sylva web site. After a bit of poking around, I found this interesting little excerpt:

"A bolt is a clamping device. It is not a pivot. A suspension mounting bolt’s primary function is to clamp the chassis mounting bracket against the bush pivot (crush) tube. The suspension does not pivot about its mounting bolt. 0.5" (12.7mm) holes are drilled in the suspension mounting brackets and 12mm bolts are supplied in the bolt pack. This results in a 0.7mm clearance. This is by design. Just to reiterate, the bolt is just a clamping device, not a pivot. If the 12mm bolts are correctly torqued, there will be no slop or play in the suspension.

Tightening Torque
All 12mm suspension bolts, 65 - 75 foot pounds."

I believe Sylva have been building cars for some time, so I presume they know what they're talking about.





The pay isn't very good , but the work's hard.

View User's Profile View All Posts By User U2U Member
JoelP

posted on 18/10/04 at 07:20 AM Reply With Quote
on every thread regarding bushes that i have read, this has been universally agreed upon. the point of contention is whether the crush tube is longer or shorter than the bush, ie whether the bush is slightly free or slightly compressed.






View User's Profile View All Posts By User U2U Member
Hugh Jarce

posted on 18/10/04 at 07:35 AM Reply With Quote
I seem to remember someone was adamant that a bolt was OK to use as a pivot.
I think it's fairly universally accepted the length of the crush tube has to be the same as the internal width of the bracket and then, if using PU bushes, they should be around 0.5mm longer overall (when assembled as a pair) than the crush tube.
Obviously solid plastics such as acetal and Nylon would need to be the same length as the crush tube.....but bush length was not what this thread was about.





The pay isn't very good , but the work's hard.

View User's Profile View All Posts By User U2U Member
James

posted on 18/10/04 at 08:15 AM Reply With Quote
As the bowl of petunias said:

"Oh no, not again"

James

View User's Profile View All Posts By User U2U Member
mackie

posted on 18/10/04 at 08:29 AM Reply With Quote
Is there a rule of thumb for what bolt diameter to use with what crush tube ID?
We are using Nissan Bluebird trailing arms with the std bushes and the ID of the crush tube is bigger than the rest of our suspension (GTS poly bush kit). I'm not sure exactly how big but i'd estimate maybe 14mm.
Also, is the idea to get the crush tube to fit as precisely as possible in the bracket so when tightened it doesn't bend inwards at all? I'd guess it is so would you just use washers to space it out suitably.

Nice little nugget about what torque to do em up to, that's a lot higher than I'd have thought!

View User's Profile Visit User's Homepage View All Posts By User U2U Member
MikeRJ

posted on 18/10/04 at 08:45 AM Reply With Quote
quote:
Originally posted by mackie
Is there a rule of thumb for what bolt diameter to use with what crush tube ID?
We are using Nissan Bluebird trailing arms with the std bushes and the ID of the crush tube is bigger than the rest of our suspension (GTS poly bush kit). I'm not sure exactly how big but i'd estimate maybe 14mm.
Also, is the idea to get the crush tube to fit as precisely as possible in the bracket so when tightened it doesn't bend inwards at all? I'd guess it is so would you just use washers to space it out suitably.

Nice little nugget about what torque to do em up to, that's a lot higher than I'd have thought!


Amazingly I have seen an "engineer" insist that the bolts were designed as the pivot and had thoroughly greased them up and fitted nylocs so the nut would saty put whilst loose enough to allow the cruch tube to rotate!

The GTS crush tubes are most likely designed to take an M12 bolt, the Luego ones are as well. Others use M10, either is more than adequate in terms of shear strength for this job.

The ID of the crush tube and the holes in the brackets should be such to give a minimal "clearance fit" to the shank of the bolt IMO (12.5mm for a M12). Excessive clearance in this application would wreck any chance of getting repeatable suspension geometry.

Idealy the crush tube should be a sliding fit in the bracket to ensure that both sides of the bracket are parallel when the bolt is torqued up.

View User's Profile View All Posts By User U2U Member
stephen_gusterson

posted on 18/10/04 at 08:50 AM Reply With Quote
all I can add is that whenever ive worked on car suspensions using rubber bushes, the suspension arms didnt flop down when diss-assembled, so the rubber stops that happenning. IE, the rubber 'twists' not the inner tube....

atb

steve

[Edited on 18/10/04 by stephen_gusterson]






View User's Profile E-Mail User View All Posts By User U2U Member
blueshift

posted on 18/10/04 at 12:03 PM Reply With Quote
quote:
Originally posted by Hugh Jarce
I seem to remember someone was adamant that a bolt was OK to use as a pivot.


Yep, it was Syd Bridge. And only Syd. Everyone else took the course of sanity.

Enough said, I think?

View User's Profile Visit User's Homepage View All Posts By User U2U Member
ned

posted on 18/10/04 at 12:05 PM Reply With Quote
James,

You must stop taking those drugs!!

Ned.

quote:
Originally posted by James
As the bowl of petunias said:

"Oh no, not again"

James


[Edited on 18/10/04 by ned]





beware, I've got yellow skin

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
DaveFJ

posted on 18/10/04 at 01:56 PM Reply With Quote
OH God - please no........


Not the great bush/crush tube deabte again??? life really is too short





Dave

"In Support of Help the Heroes" - Always

View User's Profile Visit User's Homepage View All Posts By User U2U Member
andkilde

posted on 18/10/04 at 03:20 PM Reply With Quote
I hear the Americans are doing away with bushes altogether in the upcoming election...



View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
mackie

posted on 18/10/04 at 03:32 PM Reply With Quote
Here we go again...
Syd,
What's the problem with this?
Is it still a bone of contention what Hugh said about the bushes being a fraction wider than the crush tube? It all seems perfectly sensible to me, you've even said on here that there's nothing wrong with the PU bush/crushtube arrangement where the bush pivots on the rigid crush tube.
A bit of clamping force on each side of the bush will stop if from slopping side to side will it not?

I don't really want to open a can of worms but reading your previous comments on this subject, I can't see what the problem is.

View User's Profile Visit User's Homepage View All Posts By User U2U Member
indykid

posted on 18/10/04 at 03:33 PM Reply With Quote
LOL andkilde


[Edited on 18/10/04 by indykid]

[Edited on 18/10/04 by indykid]






View User's Profile Visit User's Homepage View All Posts By User U2U Member
Northy

posted on 18/10/04 at 05:22 PM Reply With Quote
Rescued attachment can_o_worms.jpg
Rescued attachment can_o_worms.jpg






Graham


Website under construction. Help greatfully received as I don't really know what I'm doing!


"If a man says something in the woods and there are no women there, is he still wrong?"

Built 2L 8 Valve Vx Powered Avon

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
mackie

posted on 18/10/04 at 05:27 PM Reply With Quote
quote:
Originally posted by Northy



It wasn't me!

View User's Profile Visit User's Homepage View All Posts By User U2U Member
stephen_gusterson

posted on 18/10/04 at 05:40 PM Reply With Quote
you had to edit that twice!!!!





quote:
Originally posted by indykid
LOL andkilde


[Edited on 18/10/04 by indykid]

[Edited on 18/10/04 by indykid]







View User's Profile E-Mail User View All Posts By User U2U Member
stephen_gusterson

posted on 18/10/04 at 05:41 PM Reply With Quote
about the bush thing....

someone said on the radio today that in Iraq


'shock and awe'

has not turned into

'aaaawwwww shucks!'

atb

steve






View User's Profile E-Mail User View All Posts By User U2U Member
Cita

posted on 18/10/04 at 07:47 PM Reply With Quote

View User's Profile View All Posts By User U2U Member
indykid

posted on 18/10/04 at 08:07 PM Reply With Quote
quote:
Originally posted by stephen_gusterson
you had to edit that twice!!!!




as i replied, mackie beat me to it, so i added a name(1 edit) then spelt that name right(next edit)

should've just deleted it really

tom






View User's Profile Visit User's Homepage View All Posts By User U2U Member
ned

posted on 19/10/04 at 09:36 AM Reply With Quote
for your info, the second time you edit a post you can delete the first bit that says 'edited by' etc so you only ever need show one 'edited by' line.

Ned.





beware, I've got yellow skin

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
indykid

posted on 19/10/04 at 10:09 AM Reply With Quote
ah touche

cheers
tom






View User's Profile Visit User's Homepage View All Posts By User U2U Member

New Topic New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.