tie rod clamp bolts are stripping/breaking

[Michael L.]

Guys,

I'm trying to tighten my tie rod clamp bolts but they are stripping/breaking. The manual says to torque these to 120-160ft/lbs so I was going with 140 but they are not tolerating it. Its a fairly small bolt and I was surprised to see the torque so high but I figured the clamp does so pretty important job so probably needs to be that high. Its possible that my original replated bolts are just not up to the task. Any ideas?

Mike

[Terry M.]

Re: tie rod clamp bolts are stripping/breaking

Guys,

I'm trying to tighten my tie rod clamp bolts but they are stripping/breaking. The manual says to torque these to 120-160ft/lbs so I was going with 140 but they are not tolerating it. Its a fairly small bolt and I was surprised to see the torque so high but I figured the clamp does so pretty important job so probably needs to be that high. Its possible that my original replated bolts are just not up to the task. Any ideas?

Mike

Mike you don't tell us what year your Corvette is, but I can't imagine there is much difference among them.
120-160 ft/lbs is way too high for those bolts. 1970 AIM shows 108-144 lb/in.

[Joe L.]

Re: tie rod clamp bolts are stripping/breaking

Guys,

I'm trying to tighten my tie rod clamp bolts but they are stripping/breaking. The manual says to torque these to 120-160ft/lbs so I was going with 140 but they are not tolerating it. Its a fairly small bolt and I was surprised to see the torque so high but I figured the clamp does so pretty important job so probably needs to be that high. Its possible that my original replated bolts are just not up to the task. Any ideas?

Mike

Mike------


120-160 ft/lbs????????? No way in the world. I don't know where you're getting this from but it's WRONG. These are 5/16-18 bolts. Using this much torque will DESTROY these bolts.

The correct torque is 132 lb/INCHES. This is 11 lb/feet.

[Michael L.]

Re: tie rod clamp bolts are stripping/breaking

Thanks Joe. I must have read the spec sheet wrong in my AIM. I'm such a dummy...NO WAY a bolt of this size could EVER have a torque spec that high. Jim Shea's article on tie rod set up states 22 ft/lbs which I'm sure would also be fine but never 150.

Mike

[Gary B.]

Re: tie rod clamp bolts are stripping/breaking

Mike,

Well I'm confused. If the 1970 AIM says 108-144 lb-in, and Joe says 132 lb-in (11 lb-ft) based on thread specs, then 264 kb-in (22 lb-ft) sounds too high. Do the tie rod clamp bolts and nuts have a high strength spec that justifies twice the typical torque for that size bolt/nut, presuming they are grade 5? Are they grade 8?

Gary

[Michael L.]

Re: tie rod clamp bolts are stripping/breaking

Gary,

Not sure what grade they are. Jim's article is the source for the 22ft/lbs torque rec and I was merely commenting that 22ft/lbs, even though it's double what Joe had said, was still way more appropriate than the 150ft/lbs I was trying to set them at. I will look again carefully at my 69 AIM and see what it says the torque specs are but if I can't find the setting then I will go with the 11 ft/lbs Joe stated.

Mike

[Joe L.]

Re: tie rod clamp bolts are stripping/breaking

Mike,

Well I'm confused. If the 1970 AIM says 108-144 lb-in, and Joe says 132 lb-in (11 lb-ft) based on thread specs, then 264 kb-in (22 lb-ft) sounds too high. Do the tie rod clamp bolts and nuts have a high strength spec that justifies twice the typical torque for that size bolt/nut, presuming they are grade 5? Are they grade 8?

Gary

Gary------


The spec I mentioned is from the 1970 Chevrolet and 1969 Corvette Chassis Service Manual.

The tie rod clamp bolts are GM 280M material grade (SAE grade 5----3 lines).

[Michael G.]

Re: tie rod clamp bolts are stripping/breaking

11 ft lbs is fine. They had a reason for that low spec, more is not necessary.

[Gary B.]

Re: tie rod clamp bolts are stripping/breaking

Mike,

If the bolts/nuts are grade 8, then they should be able to take 22 ft-lbs. But if they are grade 5, then I would not use 22 ft-lbs.

Gary

[Joe L.]

Re: tie rod clamp bolts are stripping/breaking

Mike,

If the bolts/nuts are grade 8, then they should be able to take 22 ft-lbs. But if they are grade 5, then I would not use 22 ft-lbs.

Gary

Gary-------


Originals were grade 5.

[Michael G.]

Re: tie rod clamp bolts are stripping/breaking

The issue is not whether the bolt can take 22 ft-lbs; it normally can, even though its a grade five. You have to consider what that torque really does.

The issue is clamp-load. More torque means more clamp-load tending to push the ears of the clamp together. 22 ft-lbs of torque applies twice as much load as intended. The clamps are sheet metal, of a design not intended to take that much load. More torque is not better.

[Gary B.]

Re: tie rod clamp bolts are stripping/breaking

Mike,

I agree with the completely with you. My question is why Jim Shea recommends 22 ft-lbs, when everyone else says 1/2 that or less. Just a mistake? Hopefully Jim can chime in.

Gary

[Timothy B.]

Re: tie rod clamp bolts are stripping/breaking

Gary,

I don't speak for Jim but I always thought a grade five 5/16" bolt torque is 20-25ftlbs, 3/8" is 30-35 ftlbs, 7/16" is 40-45ftlbs so I can understand why he recommended the 22 ftlb. spec.

In this instance, inlbs is better because all you really want to do is compress the clamp so the sleeve has friction against the threads. With the clamp, I doubt if the bolt and nut would tighten square which may lead to it breaking even at the 25ftlb torque spec. plus all you accomplish is to distort the clamp ends which make future adjustment difficult.

[Gary B.]

Re: tie rod clamp bolts are stripping/breaking

Timothy,

Taking a quick lock at the suggested assembly torque values from the American Bolt Corp, their table lists 13 and 17 ft-lbs for lubricated and dry installation of 5/16-18 Grade 5 bolts. Grade 8 values are 18 to 24 ft-lbs, lub/dry respectively. But as we know the tie rods bolts are Grade 5, so 22 does seems excessive and I would worry about clamp deformation as well as the lesser likelihood of bolt/nut stripping/breaking.

Gary

[Jim S.]

Re: tie rod clamp bolts are stripping/breaking

The following is also posted in a previous thread on tie rod ends with RH and LH threads.
Jim

I have an assortment of AIM sheets and Chevrolet Shop and Overhaul Manuals. It is sort of scary to note how the tie rod nut torque specs vary within these documents.

1975-76 Corvette AIM, Relay & Tie Rod Clamping Instructions UPC 9D sheet #3. It calls out a torque spec of 108-156 In-Lbs on all four tie rod clamp nuts. Converting to Ft-Lbs would be 9 - 13. The mean would be 11 Ft Lb. The drawing torque spec symbol points directly to the clamp nut.

1968 Chassis Service Manual shows a torque spec of 10.8 Ft Lbs.

My 1966-79 Corvette Shop Manual (Tune-up & Maintenance Guide) shows a mean torque spec of 11 Ft-Lbs for those nuts.

My 1971 Chassis Service Manual shows 22 Ft-Lbs for the tie rod clamp nut in the Specifications, Page 25, Torque Chart

My 1971 Chassis Overhaul Manual shows trucks with a tie rod clamp bolt spec of 11 Ft-Lb (except K series which is 35 Ft-Lb) and passenger cars with tie rod clamp nut specification at 22 Ft-Lbs (except Nova which is 12.5 Ft-Lbs).

The 1975 Chevrolet Service & Overhaul Manual Supplement shows Tie Rod Clamp Nut spec of 22 Ft Lbs for all Passenger Cars except Corvette which is 11 Ft Lbs.

I think that the 22 Ft Lb spec is incorrect. Where it came from - I do not know. I would only trust the torque spec listed in the AIM sheets.