The Stovebolt Site Forums The Shop Area Driveline Wow!

the past few days I've noticed a small rattle sound when I started up the 50. I would hop out open the hood and the noise would go away. I would hop back in and the noise would come back.

Was not a major sound, sounded like a small bell or two tubes clanging. I drive my truck to work so Off I would go.


Well this morning I was determined to trace it. Started her up and the little rattle would start. Hop out it stopped. Opened the hood. No sound. I leaned on the drivers fender and a faint ringing would start.

Laid under the truck and couldn't see anything obvious.

checked out the disc brakes...nothing.

then the Snake bit me

...video...
...QuickTime...



I know what I'm doing on my next day off

I didn't think you guys in the no snow zone had potholes to beat up your suspension.

You'd wonder why it would break even.... must be from jumping it.....:-)

John

Wow, good catch!

I found both front upper shock mount on the truck had previous weld repairs when I took the truck apart in 07.

...pic...

My guess is they were welded before Dad bought the truck in the early 70's
I just ordered replacements from classic parts.

Is there a certain grade fastener I should used to bolt the new upper mounts?
Or will grade 5 work.



I've driven the truck to work a few times with the mount broke like that. Strange thing is that there was no change in handling at all.

The bolts did not fail and the shock did not fail so I would use grade 5. The bracket? Only times I have seen that kind of fail is when a curb was jumped or a loaded truck hit something like a chuck hole or rock...Good find by the way.

Seems like the suspension stops should have prevented bottoming out to the point of stress and if the shocks allowed the correct extension, then again there wouldn't be excess stress. I'd double check they are the correct ones.

Dennis

I would go with Grade 8. Its not quite as strong as the original rivets but it will come close enough. As you can see, great force was applied off and on for several years which worked the welds loose. Its not that much more expensive between 5 and 8 so its just insurance.

I had to buy one of these. Just know that they are not exact replicas of the originals. Different curves to them.

Scott

I was afraid of that.
Do the mounting holes line up?

I really don't like the idea if grinding off the rivets

I have found that drilling out the center of a rivet than using a chisel on the head works well.

There were a few different designs for this piece. Some were flared a great deal and others were just flared what they needed to be. Not sure what the vendors are selling. In any case, you will have to grind off the rivets. If you were willing to drive to Kansas, I would help you put the rivets back in, but grade 8 bolts will work JUST fine. I THINK the mounting holes will line up with the vendors offerings. I have some extra ones lying around if you need a more exact match, MAYBE I have what you need. If the vendors picture looks like yours, you are good to go.

A few things to think about when installing the new ones. Chances are, the holes are exactly 3/8". Take your drill bit set and grab the 3/8 one and check the new piece. Chances are it fits perfectly. Tight, but perfect. Next, Once you have ground off the rivets, check the same way. The hole should be pretty tight. You WANT as tight as possible using a grade 8 bolt. I know this is not your first rodeo, but be sure when you grind off the rivets, you don't grind too deep. Then, use a 3/8 by 24 (fine thread bolt)/nut combination. Fine thread is stronger than coarse. If I am wrong about the 3/8 size, just adjust for the size the frame is after removing the rivet. Chances are the frame will be bigger than the vendors part. The vendors part holes WILL line up just fine. Keep us posted!

McMaster-Carr or Fastenal is a good place for sourcing the bolts and nuts. I say 3/8 because Chevy used 3/8 rivets for almost every rivet on the frame. Check before you order.

Ideally you would want a bolt not threaded all the way to the head. Threads that are punished like what you show will wallow out the bolt holes. I'll be interested to know if the shocks check out as proper as they don't look like they are spec'd for the up/down travel you've seen.

Dennis

I used shocks from autozone

...link...

The mount broke where a previous weld repair had been done.
The rivets are still in place. Just the top of the mount broke off.

Both front mounts had this weld repair.


Thanks for the tips.
I ordered new mounts and should arrive next week.
Not sure if I can get a bolt with a shoulder that short. But I'll look.


I'm still amazed haw this would go unnoticed while I was driving it around including on the highway. Not a hint of handling problems.

That would be hard Dennis, since the bolt length we are talking about here is 1/8" frame, and just a tad less than 1/8 inch for the part, so that's 1/4 plus another half inch for the nut and locknut, so 3/4. Maybe they are available with a little less than a 1/4" smooth area, but I haven't seen them. Thus the reason for rivets.

I agree its very important to be sure your shocks are the right ones first.. for sure. Once you have determined they are, grade 8 bolts will be just fine. Cinch them suckers down real good! LOL!

There is also the possibility of re-welding the part. This time a little hotter. Saves the rivets.

OK, an old weld so the problem was from before since you are using standard shocks. You could probably go with an AN spec'd bolt. They come in varying grip lengths.

Dennis

I had to grind off the rivets on my rear leaf spring brackets.... get them hot with a torch and then use a air chisel and it shouldn't be an issue. i started out using a sledge and chisel.... (big mistake!)

Welds are never as strong as base metal and typically weaken the piece just beside the weld itself. I have not viewed your links but without looking I bet the failure was near the weld bead but not the bead itself. This area called the HAZ heat affected zone. Is why TIG is Strongest weld has smallest HAZ.

Having failed once another reweld of the same type in the same place will likely fail again. I would recommend something different this time, either bolting or adding gussets or other material to support the weld.

Dennis is correct on using shoulder bolts so threads do not wallow the holes. McMaster Carr or Aircraft Spruce will most likley have the right size. Fastenal has less selection...in my opinion.

On rivets I cut an X in the rivet head with a cutting wheel, cut the head off with a chisel in the air hammer, then put a punch in the air hammer and punch the rest of it out. With a good air hammer the rivets will be flying around the shop.

This after some number of less effective methods.

During chassis restoration, I removed all four shock mounts to clean rust trapped between. But most importantly so that I could easily replace the mount in the future. Broken mounts are not that uncommon and two of mine showed signs of welded repairs. I insured the bolt holes were just large enough to accept the bolt. Start with one, bolted to frame and then drilled the others out through bracket and frame together to ensure perfect alignment of holes.

Yeah, don't beat on the frame with a hammer. It can bend and look really bad. I use my Makita to grind the head off, then a good punch to drive the rivet out. (If you don't have air chisels, etc.) Not a lot of room under there I know.

All good suggestion
Thanks
I appreciate the tips

Here's a close up pic of the top that broke.
...pic...

...pic...

I don't have a full shop, no air hammer.
Ill be working from the well side so I hope that's the side with the head.
I probably end up drilling the centers and try a hammer and punch, Mapp torch if needed.

Did the holes in the replacement not line up with the rivet holes on the frame?

I removed two bad rear shock mounts on a 54 3100, using the same procedure as described by Deve. The old mounts had become deformed and had wallowed-out holes, due to loose shock bolts.

I think I used rounded-head (not slotted head) high-grade SS bolts from Totally Stainless. It looks OK and seems to be OK for my easy-going cruising. I check the tightness of all my bolts every year during end-of-hibernation check-out.

Sorry Gus my computer went ballistic on me last night. To answer your question, yes they line up perfectly. I will pm you with a photo of the original and the one from chevy parts.

Scott

There is no 'HEAD' per say on the rivet. Both sides are the same, so no worries on which side you work from. Since your holes are probably not messed up since the rivets are tight, chances are you will have an easy time of it. Probably no need to drill anything.

They did, but drilling out separately could result in slight misalignment and I used a drill bit that just allowed the 3/8" bolt to pass. I did not want the bracket to be able move around and cause wear on bolts.

If you grind the head off, then take a punch to punch out the rivet, being careful to not punch on the frame, just the center of the hole, you might not have any damage to the 3/8" hole. Not sure how much of a swing on the hammer you are going to get under there though. That's where a 1/8 or so drill hole in the center of the rivet to relieve pressure could be the way to go.

While you are waiting for the parts, wouldn't hurt to spray some PB Blaster around the rivets.

finally had a chance to replace the upper mount today.

Not to bad of a job, took about 2 hours.
ground the heads flush from the inside.

knocked the rivets out with a punch fairly easy QT
used 5/16 NF x 3/4 grade 8 fasteners.
that is what the hole in the frame and new part accepted.
I had 3/8 NF ready to go also, just in case.

fame holes where in good shape. Didn't need my torch.

thanks to all for the help.

on a side note I've been driving the 50 for the last 4 weeks with the left shock mount missing. No issues at all. These are great old trucks.

Nice video. And thanks for letting us see the one that did not want to let go. Honesty is still the best.