'79 yaws under acceleration
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
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From: St. Petersburg Florida
'79 yaws under acceleration
My '79 has started to yaw to the right under acceleration. When I let off the gas it will come back straight. I have looked over the suspension and don't see anything obvious that would cause it.
I had a '69 that did this and it was caused by the left trailing arm that had started to fail and would bend from the torque but that's not the case now.
Any suggestions on what I should look for?
I had a '69 that did this and it was caused by the left trailing arm that had started to fail and would bend from the torque but that's not the case now.
Any suggestions on what I should look for?
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
Likes: 147
From: St. Petersburg Florida
Melting Slicks
Joined: Dec 2008
Posts: 2,070
Likes: 5
From: N.Richland Hills Texas
My '79 has started to yaw to the right under acceleration. When I let off the gas it will come back straight. I have looked over the suspension and don't see anything obvious that would cause it.
I had a '69 that did this and it was caused by the left trailing arm that had started to fail and would bend from the torque but that's not the case now.
Any suggestions on what I should look for?
I had a '69 that did this and it was caused by the left trailing arm that had started to fail and would bend from the torque but that's not the case now.
Any suggestions on what I should look for?
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
Likes: 147
From: St. Petersburg Florida
Is there a way to check the trailing arm bushings without pulling the trailing arms. I tried using a crowbar to check for play but didn't have any and from what little I can see of them they don't appear to bad.
Or should I just change them because that's most likely the problem and they're inexpensive.
Or should I just change them because that's most likely the problem and they're inexpensive.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
The bushings are not expensive, true. But the job can be a PITA. Sometimes, the bolt that holds the front of the trailing arm to the frame rusts in place, and can be a huge nuisance to remove.
Part B of that is that the bushings often last a long time, and don't need to be replaced until you damage them while attempting to remove them.
My personal vote is your problem is a worn bushing set that holds the nose of the diff to the crossmember, or bad wheel bearings or just plain bad alignment.
Part B of that is that the bushings often last a long time, and don't need to be replaced until you damage them while attempting to remove them.
My personal vote is your problem is a worn bushing set that holds the nose of the diff to the crossmember, or bad wheel bearings or just plain bad alignment.
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
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From: St. Petersburg Florida
The bushings are not expensive, true. But the job can be a PITA. Sometimes, the bolt that holds the front of the trailing arm to the frame rusts in place, and can be a huge nuisance to remove.
Part B of that is that the bushings often last a long time, and don't need to be replaced until you damage them while attempting to remove them.
My personal vote is your problem is a worn bushing set that holds the nose of the diff to the crossmember, or bad wheel bearings or just plain bad alignment.
Part B of that is that the bushings often last a long time, and don't need to be replaced until you damage them while attempting to remove them.
My personal vote is your problem is a worn bushing set that holds the nose of the diff to the crossmember, or bad wheel bearings or just plain bad alignment.
I'll check the differential bushings. I didn't really check around there as I figured the problem would have been in the outboard suspension.
If it were wheel bearings would there be any noticeable play in the hub?
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Team Owner
Joined: Jan 2006
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From: Crossville TN
Possibility of left motor mount separation???? Open the hood with engine running; quickly rev the engine and watch for movement. Normally, you will get a little bit of 'twist' from the engine torque with a good [rubber] mount. If you get a lot of movement, take a good look at that left mount.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Possibility of left motor mount separation???? Open the hood with engine running; quickly rev the engine and watch for movement. Normally, you will get a little bit of 'twist' from the engine torque with a good [rubber] mount. If you get a lot of movement, take a good look at that left mount.
OP, my car did the same thing. I replaced the trailing arm bushings and now all is fine. Luckily the bolts came right out.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Just had the car aligned when I put tires on it a couple months ago.
I'll check the differential bushings. I didn't really check around there as I figured the problem would have been in the outboard suspension.
If it were wheel bearings would there be any noticeable play in the hub?
I'll check the differential bushings. I didn't really check around there as I figured the problem would have been in the outboard suspension.
If it were wheel bearings would there be any noticeable play in the hub?
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
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From: St. Petersburg Florida
Melting Slicks
Joined: Oct 2005
Posts: 2,056
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From: Redruth Cornwall
Did it do this before the tire replacement and alignment?
If not, perhaps they messed up the settings. You wouldn't necessarily see unusual wear if the tires are very new with low miles on them.
Hopefully a cheaper and easier fix than doing the trailing arms.
If not, perhaps they messed up the settings. You wouldn't necessarily see unusual wear if the tires are very new with low miles on them.
Hopefully a cheaper and easier fix than doing the trailing arms.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Trailing arm bushing problems can definitely cause steering 'wobble'. But, whether BASHCROFT knows it {or not}, a bad left mount can cause the car to tweak to the right at WOT.
You already had input on the T/A bushing issue. I was just offering another possibility for you to consider.
Bashcroft: Why are you always so disagreeable? Or are you just a 'natural' a__hole?
You already had input on the T/A bushing issue. I was just offering another possibility for you to consider.
Bashcroft: Why are you always so disagreeable? Or are you just a 'natural' a__hole?
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
Big blocks were notorious for this. Mounts were fairly weak and it was pretty easy to rip the left front mount out. It would not only pull to the right but the motor would actually lift and bang on the hood if the mount was completely torn.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Trailing arm bushing problems can definitely cause steering 'wobble'. But, whether BASHCROFT knows it {or not}, a bad left mount can cause the car to tweak to the right at WOT.
You already had input on the T/A bushing issue. I was just offering another possibility for you to consider.
Bashcroft: Why are you always so disagreeable? Or are you just a 'natural' a__hole?
You already had input on the T/A bushing issue. I was just offering another possibility for you to consider.
Bashcroft: Why are you always so disagreeable? Or are you just a 'natural' a__hole?
Le Mans Master
Joined: Oct 2010
Posts: 6,936
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
something may be sloppy back there. i have a friend that thought he had big problems because on hard acceleration the car slid the rear over, and that was just a tire pressure adjustment. when mine does that i adjust the air pressure. that isn't the issue your having is it?
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
I'm going through that now. I was able to pull next to my black truck and see the rear wheel in the reflection. It doesn't move much, maybe a 1/2 to 3/4 of an inch going from drive to reverse.
Using a pry bar to wiggle things doesn't work well.
Using a pry bar to wiggle things doesn't work well.
Thread Starter
Pro
Joined: Jul 2012
Posts: 707
Likes: 147
From: St. Petersburg Florida
something may be sloppy back there. i have a friend that thought he had big problems because on hard acceleration the car slid the rear over, and that was just a tire pressure adjustment. when mine does that i adjust the air pressure. that isn't the issue your having is it?
I know the alignment is good. I work at a dealership and the tech is is excellent.