I've noticed that under moderate to hard acceleration my car seems to lift a little - mostly the front left. When it does the car pulls a bit and then when I lift off the accelerator to shift it pulls back the other way. Didn't notice it till fairly recently. Only two changes have been the carb tuning (which did result in noticeably more torque :) ) and hitting a pot hole big enough to put a small dent/flat spot on the rim of my front left wheel. Car still tracks straight, no signs of damage to the front suspension, and I took the shock off to see if maybe the rebound valving was blown - it seems good. Haven't had alignment checked yet - what else would you check?
Torque-induced precession? Maybe you need a little more right rudder during takeoff.
I'd take a look at the rear alignment to see if there is any thrust vectoring going on.
Lower air pressure in the right rear tire than in the left rear?
Hello Rob when the car starts doing that the car starts getting fun the way I see it you have three things to adjust if the issue is the rear end of the car controlling the front end which it should do I would start with looking at the toe adjustment keep in mind that depending on what kind of bushings you have the car will tighten the toe under hard exhilaration that means it wants to toe in the rear my car it toes out two more degrees right side then left side when the motor lifts the left front of the car it puts more weight on the right rear so the right rear should want more outward toe then left the next thing to look at is tire pressure trial and error will tell you what pressure gives you the most bite normally less pressure bites harder I would try not to very left to right pressure more than about 3 pounds first find a good baseline pressure that your car likes the next thing to adjust gets a little bit trickier but it will affect the car more than anything and that is the pre-load right to left on the sway bar I don't know what kind of adjustment you have on your sway bar but it should have a higher percentage of downforce on the left rear taking advantage of the car leaning on the right rear just because the car is leaning to the right does not mean it has to have more load on the right side tire the sway bar can keep the left side tire with the exact same amount of downforce no matter how much the car leans to the right when you start playing with sway bar adjustment you may also want to adjust the rear spring preload at the same time the most important thing in making these adjustments is right down each change you make and what it does to the car and do not adjust more than one thing at a time without testing tuning rear suspension is like making love to a woman you have to learn to massage it just right until it responds to your touch when you get it just right you'll know it because she'll scream LOL if the rear end of a car is set completely neutral and it gets a good bite it will turn left so hard it's almost unbelievable all because of the added weight or download on the right rear you cannot stop the torque of the motor from lifting the left front but you can compensate for it in rear suspension adjustment if you adjust something that makes the car turn right under a hard launch not tire pressure you have found the best adjustment spot for your car as long as the car still drives straight under normal driving what is normal driving? Signed more fun than a barrel of monkeys
Hello rob Im just throwing this out there but if this just started after the pot hole I would check the crossmember bolts that could make it handel like that good luck and let us know how you make out
Rob,
Check your track measurements and, also, if you can, front suspension geometry. Your left front wheel may be jacked back a hair or the rear axle is jacked back a hair. It doesn't take much. I chased the same problem on a '57 AH 100/6 after I restored it. Took forever to figure out the axle was about 2mm out of kilter.
After changing motor mounts, front bushings, super expensive (in the 70s) alignment shop, etc. Pulled the rearend after an old racing dude suggested the rearend was bent. Measured and measured and I couldn't cipher the discrepancy. Took it to a machine shop with a proper jig and micrometers and, there it was! Changed everything.
Cheers,
Tim
Thanks for the ideas. Been traveling pretty much since posting this - Mexico to build a house (church mission project; my 4th and our church's 22nd); then Singapore for work. Back home now - son ran the riding mower w/no oil - blew up motor; connecting rod seized to crank and then disintegrated. Have to fix that before I get some time to figure out the car.
Quote.....son ran the riding mower w/no oil - blew up motor; connecting rod seized to crank.....
Boy, doesn't that sound familiar - happened the same way at our house a few years back.
Glad mine doesn't use or leak oil, cause I'm sure my son never checks it!
Torque steer what is it? Here are a couple videos that show real good examples of what a fast car naturally wants to do the first video. Titled first pass on spray is a fairly mild streetcar with a professional driver and an unbelievable transmission T5 the camshaft it's in my car is the cam used in Dino testing to build that motor I bought my cam from that engine builder cam and lifters used for 60 bucks it was his cam for testing cylinder heads in the Dino room it came with 12 different Dino Sheets and a lot of other good information the second video is just something I found on YouTube
https://www.youtube.com/watch?v=1hQ-W-pMvx8
https://www.youtube.com/watch?v=b_napOis7zs
Yeah, I've seen the tendency in drag racing, but mine is doing it in semi-spirited street acceleration. I'm not dumping the clutch or accellerating hard enough to break the tires loose.
Hello hey Rob it's me again rear end torque steer use more noticeable under moderate acceleration versus breaking the tires loose when the tires break loose they're not pushing the bushings as hard as when the car is hooked up I would guess you have enough miles on your car that the bushings in the rear which looking at photos I count 12 bushings all designed to control the wheels lateral movement no bushings installed to control movement forward and backward a fast TR six will not run on rubber or urethane bushings and their bushings are set to control forward and backward more than lateral that is why Richard good came up with his NilTron bushings I would guess your car is getting enough miles on it that the bushings probably urethane can no longer control the rear wheels the good news there is a very simple test tie the front end of the car to the ground solid get in the car tried to gently take off watch the forward movement of the rear wheels if the wheel center moves more 1/8 of an inch you will know urethane bushings cannot handle it hard nylon bushings are very cheap and easy to make my car runs all steel bearings if you talk to Ted Lathrop he likes hime joints I am guessing if you try that test on your car you will probably find 3/8 of 1 inch of movement possibly more that will more than explain torque steer signed IRS is still my preference
I finally got a chance to look at the car today and looks like I found the source of the torque steer... with the back end up on jack stands I can wiggle the left wheel without much effort. Not an inch, but probably 1/4". I was by myself & dark out so it was hard to see where the movement was coming from. But, I didn't see the control arms moving so I think it is the bearing assembly. About a year ago one of the bearing assemblies was bad. I didn't keep notes & don't recall which side it was. If it turns out it's the same side, what would cause them to go bad so fast?
OK, it was definitely a failed hub. Thanks for the info Tom, you led me to it. Replaced it with a new one and torque steer is gone. Got a 3 year warranty this time - at least if it fails again I can get it replaced. Old one came from RockAuto. Was disappointed with them... I'd called Raybestos to confirm the axle nut torque setting and when they heard it failed in about 3k miles they said they could analyze it in their lab to figure out why it failed. I'd have to have the dealer I got it from send it to them but there'd be no charge. RockAuto's position, however, was once the part is out of warranty they don't want anything to do with it.
Hello Rob that's great the hub is a rather unlikely thing to go bad you would think I hope that fixes your problem
The hub is a bearing hub assembly from a 4x4 S10 pickup. It's used by a lot of custom and after market IRS's including many Factory Five cobras. Apparently they fail enough there's lots of forum chatter and improper torque seems to be the leading (perceived) reason - and different year ranges of S10's called for different torques. My 95 S10 pickup 4x4 brim hubs (used in my IRS) call fro 181 ft/lbs... I triple checked the torque this time.
But, I'm not sure torque was my problem... Mine were originally salvage yard parts and one was bad pretty much from day one (less than 20 miles anyway). I replaced it but don't recall if i did both or not. Thought I did, but now not sure. Reason i'm not sure is i know i bought 2 hubs. I kept the old ones. When this one failed, i opened the box with the old ones and one is clearly used. The other has light surface rust in a couple of spots but is definitely way cleaner and looks like it may be one of the new ones... so, now i'm wondering if I inadvertently put the used one back on?!?! Since I wasn't sure I went ahead and put a new (3yr warranty) hub on this time.
Frustrating thing is Raybestos offered to analyze my hub in their lab, but I had to have the dealer I got it from send it to them. Called RockAuto (where i bought them) and they had no interest in helping. Basic message from the support guy I talked to was once it's out of warranty they have no mechanism to receive it back and do anything. Needless to say my new one this time came from my local parts store.
Resurfacing this thread for some thoughts... while I had my car up on jack stands, I checked the rear suspension too. It's only been 5 months but both hub/bearing assemblies are already showing signs of wear. The left side in particular has some noticeable play. This is the 2nd new hub on that side in less than 4k miles. Since improper torque seems to be what most folks say is the cause of failure, and since I was having to use a rented torque wrench (spec is 181 ft/lbs and mine only goes to 100) I got two different torque wrenches the last time. I torqued it with one and then checked it with the other so I am very confident it was torqued to spec. The hubs i got have 3 year warranties so it wont cost me to redo them, but what else might be causing them to wear out so quickly?
Hello Rob I have no idea what you're hubs came out of so I cannot say for sure but I know with the Nissan hubs that I use S 13 platform they call it Nissan used it from 1990 to the present the Nissan guys will not run a aftermarket bearing you see good factory bearings on eBay selling for twice what a new aftermarket bearing costs they claimed aftermarket bearings never last more than a year my bearings had 60,000 miles on them when I got them and I have put another hundred thousand miles on with no problems mine do have a small dust seal between the bearing and a half shaft the half shaft slides into the seal you might check to see if that seal fits correctly if you have one I think it's great your at least wearing out parts driving the car most people that have nice cars never drive them
those bearings should think they're on vacation in a car is light as yours they had to of been designed for something heavier than that
The hubs I'm using are Chevy S-10 4x4 hubs. Definitely way heavier than my car -- don't get why they're wearing out. My car tracks straight & tires aren't wearing funny -- so can't imagine alignment is causing them to wear.
You mentioned "seals" -- hmmm. That is interesting and could explain the problem. The uprights on my IRS are basically just plate steel with a hole in it. The hub bolts to the outside & the axle stub passes through the hole from the back side. There is no provision for a seal... Guess I need to figure out if there's supposed to be a seal or if the S10 hubs have integral seals?
If not that, what else might cause them to wear so quickly - it's only been about 4-500 miles since I replaced them the last time??
Rob, S10 has sealed bearing hubs. I would buy GM OEM. The aftermarket stuff is usually made offshore. The Fiero guys (Rodney Dickman) sells a replacement hub that has tapered roller bearings for the Fiero because of the inferior replacement parts. I don't think there is one available for S10 axle spline.
Checked into GM hubs... will have to see if I can get them more reasonably. Chevy dealer wants $591 each!
Since the ones I had were 3yr warranty ones, I went ahead and swapped them out so I could get the car back on the road.
Any other ideas why they are wearing out so fast? I get that OEM should be better, but surely even after market should be getting better than 500 miles.
Some info that might help diagnose:
- Left side is wearing out noticeably more than right.
- Right side was just starting to show wear
- There is a cast aluminum bracket for the brake caliper, about 1 1/2" thick, that is bolted between the upright and the hub.
They have about a 3/16" hole that might be a drain hole. On the right side it is at the bottom. On the left side it is at the top.
Car has only been in the rain 2 or 3 times in the last 500 miles.
- Uprights are steel plate, about 1/4" thick with another 1/2" plate welded (TIG) on the outside
(extra 1/2" was added because lower control arms rubbed on back of wheels when IRS was being designed/built).
Uprights are powder coated. Have wondered whether welding may have introduced slight warping - thinking unlikely
given thickness & TIG?
- Don't think it'd be affecting the rear hubs, but I did find the bolt going through the him that ties the steering arm to the
front upright was loose - note to self and others, check under the car more often!! That could have been disastrous.
Rob, Those are probably ABS sensor holes. Do a search on greasing the sealed bearing hubs. Probably too late for those but I did a search and you can make a tool with tubing to fit in the ABS hole with a 90 degree grease fitting and grease your new ones. Holes should be on top both sides. One guy took apart a set of hubs and there was just a little bit of grease on one side of the bearings .Don't fill them until you blow the seals. just a little expansion or grease showing at the seal. they can vent through the ABS holes. They should still last 100,000 miles normally. Do you have extreme camber on your rear wheel alignment or is your rear wheel offset extremely negative? Try a dial indicator and check for runout on your new hubs to see if they are square to your uprights.
Hey Rob,
the most common failure mode that I see is axle nuts that aren't torqued up fully.
In your case they should be somewhere around 180 ftlbs. (which is really tight)
The axles are the only thing that hold the bearings together.
The second and hardest to trace, is poor drive train grounding.
If your engine ground is weak or non existent, starting the car causes the battery to look for a path to the starter.
Often this is through your throttle linkage which melts of jams up inexplicably.Or the speedo cable which does the same.
The next most likely path is through the trans, to the driveshaft, to the diffy, throught the drive axles, across the wheel bearings and finally through the suspension to ground.
In this situation any one of the bearings in the chain can be affected. From trans to diffy. I've even seen a syncro welded onto it's cone.
Cheers
Fred
Jim, you might be right on the holes. The hubs have an ABS ring on them so it makes sense that there'd have to be a sensor and the wires would have to go somewhere.
Fred, I think my ground is good. I have a 1/0 ground running from the battery up to a bolt on the frame. Fastened to that same bolt is a braided groung strap that goes to the block. I also have another braided ground between the trans tail section and the rear cross member.
But, your comment combined with Rick's post about his header bolts has me thinking. The left hub was warn enough I could wiggle it by hand. But, after knocking out the lugs, I was no longer able to wiggle it as if knocking out the lugs pressed it back together.
Before removing the hub, I checked the axle but and it was tight, but I didn't check it with a torque wrench to see how tight.
Make sure that the nut is tightening up against the bearing and not just bottoming out or something similar.
Woo-hoo!! I've finally figured it out.
Hubs failed again. Has been 3 months & about 600-700 miles. So, I took them apart again today. 1st clue was the right side one was difficult to pull off the stub axle. I had to make a puller to get it loose. I was taking some pictures to show some folks on an IRS board & on one of the stub axle, the flash caught an area that had been rubbed thru the paint. So I started looking closer... found the diameter of that part of my stub axle is about 0.07" bigger than the hole thru the bearing assembly - keeping them from seating properly. You can see where it's hitting on the inside of the bearing assembly.
So, now I just need to decide what to do about it. If I had a lathe, I'd just turn it down to fit, but I don't. So, I'm going to call the folks who made the axles & see if the Nissan CV's will fit the axle shafts they used -- I still have the old Nissan CV's and the stub axle portion fits the S10 bearing/hub assembly so swapping them out would be the easiest fix I think.
CORRECTION: The issue isn't the diameter of that stub axle section, it's the length of it.
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Good eye Rob.
You can use a shim to take up the clearance.
Any good trans shop should have a selection of hardened shims that would work.
Cheers
Fred
Good to know Fred. I sent an email last night to the folks I got the axles from ("The Drive Shaft Shop" in Salsbury NC) and had a reply already this morning. Recognized the problem immediately, apologized, told me they were supposed to machine that area, said they'd fix it, issued RMA number, and said they'd send me a return mailing label. Can't ask for better support than that!
Oh yeah, I did some measurements on the Nissan parts. All the length dimensions for the CV joint and stub axle were good, but my drive shaft shop axle shafts are 1" vs 26mm for the Nissan ones so the CV wouldn't fit.
Rob, Congrats on finding the issue and reporting back to us. Too many threads build up and then disappear without resolution. This info may help someone else in the future
Glad to hear you found the problem.