Thread: Need diagnostic help on SEVERE steering wheel shake

Tweet

I know that you said that you had your bearings checked a couple of times.... but I'm thinking this is the area of your problems. DW is a fairly common problem in Model A's and it is generally a bearing or king pin issue that causes it. I know you said that you checked it... so I'm waiting to see what the problem actually turns out to be caused by.

Thanks for keeping us updated.
Jerome

Originally Posted by MRJB1929

I know that you said that you had your bearings checked a couple of times.... but I'm thinking this is the area of your problems. DW is a fairly common problem in Model A's and it is generally a bearing or king pin issue that causes it. I know you said that you checked it... so I'm waiting to see what the problem actually turns out to be caused by.

Thanks for keeping us updated.
Jerome

You're welcome! I should have more information Tuesday after my morning visit to the front-end shop.

Originally Posted by sfort

Could you have switched these from side to side? Without strut rods it would be easier to mix up.

Don't believe so ... but worth checking. Someone also suggested reversing the tie rods as a possible solution...

Bart

Its going to be a long wait til Tuesday so don't make us wait til Wednesday!!!!

Originally Posted by jerry clayton

Its going to be a long wait til Tuesday so don't make us wait til Wednesday!!!!

fair enough!

UPDATE! UPDATE! decided to check a few things before Tuesday's trip to the front end shop... Took off the rims, static balanced them... remounted and went for a drive... Same problem started. Had one of my sons in the back seat to check for vibrations from drive shaft. Nothing,...;

Wait, here it comes...


Drove home, put her on the lift to check balance... Did some "Power Braking" to see if possibly the engine or tranny mounts had broken, normal rocking in both 1st and Reverse......''

Ready? GUESS WHAT!








FRONT WHEELS WERE COMPLETELY LOCKED UP!

Hubs were too hot to touch and there was bluing on the disc surfaces!

Had my son-in-law open the valve on the front passenger caliper, let out brake fluid under pressure and both front wheels turned smoothly! Didn't check the rear wheel, should have. At this point, I'm fairly certain it's related to either the master cylinder, booster or proportioning valve.... We had replaced the first 2 items around the same time we rebuilt the front end! This makes some sense as the brake pedal takes a while to build up pressure in the booster and, once it's built up, seems to be hyper sensitive with very slight play!~ The system must not have been able to depressurize itself! Thus, after stopping, applying the brakes, the discs cool off, pressure bleeds from the booster and the lines, allowing the car to run fine until it builds up again!

Tuesday night I'll remove the cylinder and check to see if there are any internal adjustments... then flush the lines, rebleed and test drive.

More after we break down the cylinder/booster!

Bart

I'd check the front brake hoses.
They can break down inside & cause a flap in the rubber on the inside of the hose.
You can push it down all you want & fluid can come out if the bleeders are open.
BUT that doesn't mean when you release your pedal that the pressure releases.
I would almost bet $$$$$ that if you try & force the piston back into your caliper w/o opening the bleeder that the piston won't go back in. This would cause the same exact problem you are describing w/your front rotors ....joe

I've had the situation that Joe speaks of. On the wifes 36 chevy with the original hydraulic brake lines/system, one of the rubber lines had a piece of internal part of the hose come free creating a "flap". Fluid would easily go out to the brakes but wouldn't return quickly. When this happened, the car severly pulled to the right (or where ever the bad hose was), and nearly pulled you off the road. It didn't cause DW but just a strong pull that caused the steering wheel to jerk so bad it nearly pull it out of your hands. Needless to say... we hunted that problem down so it wouldn't show up again.
Jerome

Originally Posted by TooMany2count

I'd check the front brake hoses.
They can break down inside & cause a flap in the rubber on the inside of the hose.
You can push it down all you want & fluid can come out if the bleeders are open.
BUT that doesn't mean when you release your pedal that the pressure releases.
I would almost bet $$$$$ that if you try & force the piston back into your caliper w/o opening the bleeder that the piston won't go back in. This would cause the same exact problem you are describing w/your front rotors ....joe

Good point, but would one expect to see BOTH wheels locked up with a flap developing on both sides at the same time?

Originally Posted by MRJB1929

I've had the situation that Joe speaks of. On the wifes 36 chevy with the original hydraulic brake lines/system, one of the rubber lines had a piece of internal part of the hose come free creating a "flap". Fluid would easily go out to the brakes but wouldn't return quickly. When this happened, the car severly pulled to the right (or where ever the bad hose was), and nearly pulled you off the road. It didn't cause DW but just a strong pull that caused the steering wheel to jerk so bad it nearly pull it out of your hands. Needless to say... we hunted that problem down so it wouldn't show up again.
Jerome

also a Good point... since I will be flushing and replacing much of the system, I am considering junking the under chassis booster/master and putting a new combo up in the engine bay, with a hanging peddle set-up, or some-such set-up... if I do this, I might as well replace all the plumbing and front brake houses rather than trying to extend / save what I have. thoughts? any suggestions for a kit which would work on a steel '34 sedan?

Bart

Bart I personally have had it happen, surprised me too.
And there is NOTHING wrong w/the booster/MC under the floor.
If these hoses are old & the car had been sitting for a while I would change ALL 3 of the brake hoses just for safety sake. I call it cheap Insurance...joe

Originally Posted by TooMany2count

Bart I personally have had it happen, surprised me too.
And there is NOTHING wrong w/the booster/MC under the floor.
If these hoses are old & the car had been sitting for a while I would change ALL 3 of the brake hoses just for safety sake. I call it cheap Insurance...joe

ok, just seems like such a pain to check and fill the reservoir (bought a "hanging plant" waterer with a long upside down J tube to fill it with... works well, but need to put it on the lift to do), plus PO has the shaft for the pedal at a very slight angle (left/right). being rather "anal" everytime I see it, it bothers me. To change it would require recutting the firewall where the peddle goes through and moving it to the side about 1". Will change all the hoses as suggested.
Bart

I don't know much about brakes but thought I might add this. Could it be a faulty residual inline pressure valve that is sticking?

next time the brakes lock up....start at the master cylinder, crack a line, then move down the system to see what unlocks the brakes. Starting at the wheel will not tell you what has caused the problem

Originally Posted by moter

next time the brakes lock up....start at the master cylinder, crack a line, then move down the system to see what unlocks the brakes. Starting at the wheel will not tell you what has caused the problem

duh, actually I knew that! Senior moment!

Another thing that can help find strange vibrations is to use a dyno to identify how the drive line is working, can also see engine and tranny mounts under load etc..