The Stovebolt Site Forums The Shop Area Driveline Bumpy Ride

Hey guys!

I am wondering what I might could do to help smooth out the ride on my 52 chevy 1/2 ton. I haven't looked yet but I am 98% sure the cab mount bushings have never been replaced. It rides pretty good until you drive over 50 mph. Even below that though when driving the rear view mirror vibrates up and down so much it will almost make you sick to look at it. What are any possible fixes for smoothing out the ride but keeping things as close to original? Would rusty leaf springs, or old leaf spring bushings need attention? What about shocks? Or is this going to just be a cab mount bushing issue?

Any help here would be appreciated.

Thanks in advance (pun intended)!

Matt - A thorough going over of your suspension (springs, bushings, shocks etc.) is certainly called for to see where your truck is condition wise. Also worth checking and rebuilding those cab mounts if they warrant the work. Another source to check is your existing tires for type (bias or radial), age and any unusual wear patterns. Don't forget to check their current state of balance. Bias ply tires are going to give a much stiffer/bouncier ride than radials. Plus if they have sat in one place for long periods of time, they can develop flat spots that lead to very bumpy rides.

Also of note is our trucks weren't really designed for higher speeds. The original suspension and steering is going to give a less comfortable ride when pushed up above the normal original operating range, especially if their is any wear or condition issues.

Thanks. Tires are radial and only 2 years old. No unusual wear on them. I did have bias ply tires on it when I first started driving and they were OLD. I drove it like that for a few months and boy did I feel the difference when I switched out to the radial.

I’ll check the springs, bushings, and shocks.

What can be done to the springs?

I imagine all that could be done to bushings and shocks would be to replace them. But what could I do to the springs if they are old and rusty other than replace them or take them all apart and rebuild them?

If springs aren’t broken or totally sacked out, you can rebush them and replace shackles on the one end and the pivot bolt-pin thingee at the other end. That would be a logical place to start. Springs can be rearched and rebuilt, but the charge for that in my area makes it impractical vs purchasing new.

Cab mounts, engine mounts, and core support mounts are all candidates for replacement. I need to do all of those on my truck. I’ve rebuilt or replaced all the suspension stuff over the past couple years.

These old trucks were not built for a smooth ride. They were built to haul a load. Unless you do a complete suspension upgrade it'll never ride like a Silverado.

Maybe you have too high of expectations.

John

What size tires? The more air they can hold, the better. Modern low profile tires won't cut it. New wheels, tires and shocks made a major difference in how my truck handles but it's no Cadillac.

Even with everything new and in working order, you're still going to be bounced out of your seat and hit your head on the ceiling when you go over a speed bump at over 5mph.

I have read about the Teflon you can put between the springs ,but don’t know how well of an improvement it would be and I have not tried it .

I have not used the Teflon strips, but I remember Evan “Coilover” mentioning they work well.

Had it in my head they were more for squeak management and not so much making a smoother ride.

Teflon inserts can help a bit with ride, but probably not enough to make a noticeable difference. My modern truck has plastic pads between the main and second leaf of the front springs. Like JW51 said, mainly for squeak management.
Old springs can wear to the point where they have a ledge at the end of the secondary leaves and when compressed more than normal on a bump can actually hit the edge of that ledge.
If suspect, the best thing to do, besides shackles and bushing replacement, is to replace the springs themselves. I replaced everything suspension related (including springs) on my '51 and it rides just fine.

The vibration you are having which causes the mirror shake is very likely caused by the drivetrain not springs or spring bushings.
If your truck has a torque tube rear end, the vibration can be coming from the rubber mount at the rear crossmember. In my opinion, that little rubber pad is there to tame vibration and not for supporting the transmission.
Another cause of that kind of vibration could be from deteriorated front and/or rear engine mounts.
Have you tried to swap the front and rear tires to see if it makes a difference?

Springs and related suspension parts don't normally create speed related vibrations. You either have tire wheel issues, or as mentioned, driveline issues.

Springs cause harsh rides similar to solid suspension, lots of sway, or poor handling, not vibrating. Have the tires balanced again, road force would be best, but any type is better than none. Check motor mounts, exhaust mounts, and rear axle mounts.

On a side note, teflon liners will smooth out a harsh ride, BUT you need good shocks to control the now softer springs. They will still have the same spring rate as before, there is just more slip between each leaf. But, the leafs need to be in good shape, no wear steps, no rust, and all the spring clamps in place. Wear steps is what happens when the lower spring wears into the one above it, creating a step. Over time the springs quit sliding and become one solid mass. When this happens, replacement is the best option. It's not hard to know when you have no spring movement, jump on the bumpers, if the truck doesn't move you spring issues.

Radial tires should be inflated to manufactures recommendations. Side wall markings are for maximum loads, find a vehicle with similar weight as your truck and use it for tire pressures. My '37 has 28 psi rear, 35 psi front, but it has a pretty narrow front tire. Most tire shops over inflate, and most tire issues show up around 40 + mph. I had Yokahama tires on a Toyota Tacoma, they vibrated every time it sat for 24 hours, it took a couple miles for them to loosen up. They did this from the time I purchased them til they wore out, cold weather was even worse.

Joe

Thanks 52Carl. This is helpful. I will check the condition of that rubber mount at the rear crossmember and the engine mounts. I have rotated my tires and don't see any difference from that.

Joe,

Thank you for this very informative post. I will check all those mounts to see what condition they are in. Not a bad idea to check the tire balance again too. My shocks are VERY old. I have no idea when if ever those were replaced. Truck definitely moves up and down when I jump on the bumpers and I weigh in at a cool 195lbs!

I understand what you meant about steps in the springs and how that causes the leaves not to slide. However….

Could you explain a little bit on the bumper jumping test? Like the truck wouldn’t move….at all?

Brand new shocks made overall handling, performance, and comfort increase by over 100% on my truck. Buy new ones ASAP. They're fun and easy to install with guaranteed instant gratification!

Front shocks, Monroe Gas-Matic 5826

Rear shocks, Monroe OE Spectrum 33049

You can see the old one in the picture wouldn't expand on it's own. There was no damping whatsoever.

Thanks Otto! I got them added to my wishlist. Sounds like a fun project to tackle and worth it from your testimonial!

Have the tires trued. By that I mean where they are shaved to be perfectly round. It will make the truck roll like a pool ball on a table.
I use fluid film on my springs for a lubricant and rust protection. This helps the springs to move independently.
Add some weight to the bed of your truck. A little weight will make the springs work and therefore soften the ride. An empty bed bounces without flexing the springs.

The rear springs on my truck were worn out, it came from the Flint Hills of Kansas, used as a plumbing and heating company truck. I could jump on the rear frame / bumper area and the only movement was from the tires, the spring had such deep steps, they no longer could slide or move.

You might also check the tune up of the engine, it might have weird miss or something causing the motor to vibrate shaking the mirror.

Check runout of the wheels. Are the wheels hub centric? If not you may need a hub spacer to get them centered. If they are not centered, you can try truing them on the hub by installing the wheel, tighten lug not finger tight, then wiggle and bounce wheel, tighten lugs 1/8 of a turn, wiggle, repeat; check runout.

My 49 had a harsh ride and I discovered I had overload springs on the rear. These were coil springs which anybody with old Chev experience has never seen. Removed them and the ride improved. It is a Canadian built and maybe coils were unique to those. Sure looked like a factory install.
Another probable cause for the vibrations is the bushing in the torque tube. The seal in mine failed and I replaced it with an Okie assembly. I was surprised when I pulled out the original bushing and saw how out of round the hole was in it.
I used teflon on my springs. I found an old "Flying Carpet" snow sled at a flea market and cut strips to fit. They worked but as they did not have edge strips like Posie's (I believe) they eventually wiggled out of place.
I have 650-15 Firestone bias-ply on the truck and they work fine. With the new rubber compound they do not flat spot if unused.

"If your truck has a torque tube rear end, the vibration can be coming from the rubber mount at the rear crossmember."

Does anybody have a picture of the rubber mount at the rear crossmember? I am wondering what condition this should be in? As I have looked at mine, it appears that mine might be missing altogether. I might just be looking in the wrong place. If anybody on here has a picture of what this looks like, it would help.

Here's some pics of the rear transmission mount from my truck. First pic is "before" and others are the process of redoing the rubber in it with 2-part urethane rubber. I used a product called Enduro Flex from Simple Resin. Link Or you can send yours to Steele Rubber and have them revulcanize it for $$$.

Then and Now also re-vulcanizes motor mounts.

www.then-now-auto.com

The Filling Station sells new transmission mounts as well as revulcanizing yours ( I think they send them out to Steele.) A new one is cheaper that revulcanization. Link

I had a 1953 Chevy 3800 several years ago now...I took the whole rear springs and hangers and rear end out and swapped out brand new leaf springs from the fine folks at STS spring company they were originally found on like a 1998 Chevy 1500... new rear spring view

I am not sure if this helped the ride or not but it still rode like a old truck to me...nothing like the way the new stuff rides for sure...

Good luck with finding the issues at hand...

MikeC

Kevin,

That looks awesome and seems like the way to go. Way cheaper than re-vulcanizing and keeps the original mount too! Thanks for sharing. This looks like the direction I will go with it! I have nothing there at all on mine. Both sides are entirely missing the rubber!

Matt, If you build plywood forms like I did, put a little silicone grease on the edges as a release agent, but don't get any on the metal or the rubber won't stick to it. I had a little issue with the forms I built leaking, so be sure they fit tight. Maybe use a little RTV to seal them around the edges.

I thought I would update everyone on this thread for anyone who may read and be in need. I finally got to replacing the transmission mount. I actually found one on Ebay for like $35 that had been used for two months. The guy said he decided to change the whole driveline so he was selling it.

Mine had no bushings left at all. It was completely sitting on the crossmember metal on metal (except for the transmission oil that had built up). The collar around the torque tube was so loose I was able to loosen it up by hand. Anyway... once I got the new transmission mount installed, tightened up that collar, and topped off the transmission oil and took it out for a drive I was AMAZED. I had set my expectations kind of low but I was surprised at how much smoother the drive was. It really made a major difference!

Now... I plan to change out the motor mounts and the front/rear shocks.

Nice score. About what I spent on the rubber material and you didn't have to mess with it.

Did the rubber material hold up well?

I used it on the axle pivots and they are doing fine. The issue I had with the first try on the transmission mount was that the material had expired and wouldn't set up. The supplier said it's only good for 6 months unless stored with a nitrogen padding. And I don't have any nitrogen. The axle pivot bushings were done with fresh material, as is the re-do of the transmission mount.

If you think that was nice, you'll REALLY love the difference in handling and performance when you install new shock absorbers.

New rims and tires of the appropriate size will also make a night/day difference in handling and ride quality.

Front - Monroe Gas-Matic 5826

Rear - Monroe OE Spectrum 33049