Rear end problem/drive train

[Bob from Northport]

We have a 1930 4 Dr. in the shop. Came in with the drive train locked up, brake system totally gone and broken in pieces. With the brakes totally redone, the car will not push forward. It binds up and locks down in about two feet. But it will roll backward. If you spin the left rear tire forward, the right rear turns the opposite direction. The trans is in neutral.
Do we have a broken spider gear?? Or?? When the car initially locked up while moving, someone pulled the car backward with a 1 ton truck trying to free up the drive train. We believe something broke at that time. Any ideas??

Thanks!!

Bob

[Mike V. Florida]

The wheel spinning part is working correctly. With both wheels in the air they will turn in different directions.

I can't think of what in the rear end would cause it to travel backward and not forward with the brakes released. The brake shoes can jam in one direction and not the other.

[Kurt in NJ]

If when the "rear" is locked the wheels spin opposite when off the ground most likely there is a gear or bearing problem inside, if the wheels won't move try backing off the brake adjustment--if this loosens them up look in the brakes

were the brakes rebuilt stock, or modified --floaters or other non stock parts

[H. L. Chauvin]

Hi Bob,

Absolutely nothing would surprise me with this most interesting happening.

I will never say I saw it all; & believe me, do not be surprised if you did not hear "The Rest of this Story."

The best advice one can sincerely give in my opinion is:

A. First to begin dismantling; and,

B. Just as important as the first may be, that the very last person to hire to help to dismantle & find out your real problem is the One-Ton Truck Driver.

It could be most interesting to hear what you find & it may not be impossible to observe that over 500 guys reviewed what you found after a totally locked drive train Model A was pulled backwards with a One Ton Truck.

[BRENT in 10-uh-C]

This has the sound of a broken pinion bearing. The differential (spider) gears are not broken based on the description that you can rotate the wheels in opposite directions when it is off the ground. This is not to say they aren't damaged from metal now.

The easiest thing to do at this moment is remove just the driver's side axle housing and remove the entire differential. To accomplish this, remove the radius rod bolt by the transmission, remove brake rods on the cross shafts, and remove the brake drum on the left side. Use the spring spreader and remove left side shackle, and remove the left side housing as one unit. Next remove the RIGHT side brake drum & hub, then slide out the entire diff assembly including both axles. This will allow the housing to be removed to where you can see inside. What you find will determine what comes next.

[Tom Endy]

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It is pretty difficult to determine what is going on inside of a banjo by sound and fury. The only way to determine is to take it apart and look. I suspect it is likely that broken teeth on both the ring and pinion gears will be found.

I recently rebuilt a rear axle assembly for a restoration shop. The car had a poorly built\modified Volvo overdrive installed. I only saw the rear axle assembly with the stub shaft sticking out of the banjo. Both the ring and the pinion gears had teeth knocked off.

When I finished a complete rebuild with a replacement R&P and all new bearings and races the shop owner picked it up and installed it back in the car. A few days later he called me and said a loud clunk sound comes out of the banjo each time gears are shifted. I went over to the shop and listened, sure enough there was a loud clunk each time the car was shifted from low to reverse and back. The owner said they put a stethoscope on the banjo with the car on a lift and the sound was definitely coming from the banjo. His thinking was that I had left too much backlash in the gears. I knew that was not the case.

I suggested he pull the rear axle assembly back out of the car and remove the overdrive and check the spline coupler that connects to the stub shaft. Sure enough it was wallowed out and had a good quarter inch of slop in it. This is probably what caused the R&P failure.

The overdrive was sent to Rich & Mitch in Bakersfield, CA who are premier Model A Volvo builders. They completely rebuilt it and properly aligned all the components so as not to wear out the spline coupler. They were not the original builders of the unit.

Once all was back in the car the clunk was gone and the car ran fine. This is a testimony of how sound can travel up and down the drive line and mislead people to draw incorrect conclusions.

Tom Endy

[Mitch//pa]

drain the fluid which will probably have metal in it and peak in the fill///drain plug holes with a light, you might see some of the problem... then take it apart ...

[H. L. Chauvin]

Not to mention any names, or in what State he resided, but I spoke to a Model A gentleman owner about 3 years ago who bought a Model A from a guy who in good faith brought his differential to be rebuilt immediately prior to his selling his car.

The seller brought the rebuilt differential back home from the rebuilder, carefully installed the rebuilt differential, & then again in good faith, sold the car.

The guy who bought the car went out on the Freeway, was cruising along when all of a sudden he first heard noises, then his rear wheels locked up. After a tow home, he told me he found no oil in the differential.

After going back to the seller, he said that the seller thought the differential rebuilder had added oil, & the differential rebuilder said he thought he told the guy to add oil after installation & prior to driving.

After hearing such a sad story, I never asked what happened next; but it always helps to hear what can happen unintentionally with our Model A's when we just make assumptions & we do not check everything "before" we hit the highways.

[Tom Endy]

Originally Posted by H. L. Chauvin

Not to mention any names, or in what State he resided, but I spoke to a Model A gentleman owner about 3 years ago who bought a Model A from a guy who in good faith brought his differential to be rebuilt immediately prior to his selling his car.

The seller brought the rebuilt differential back home from the rebuilder, carefully installed the rebuilt differential, & then again in good faith, sold the car.

The guy who bought the car went out on the Freeway, was cruising along when all of a sudden he first heard noises, then his rear wheels locked up. After a tow home, he told me he found no oil in the differential.

After going back to the seller, he said that the seller thought the differential rebuilder had added oil, & the differential rebuilder said he thought he told the guy to add oil after installation & prior to driving.

After hearing such a sad story, I never asked what happened next; but it always helps to hear what can happen unintentionally with our Model A's when we just make assumptions & we do not check everything "before" we hit the highways.

Any rear axle assembly I rebuild does not leave my shop without a tag hanging on it,

NO OIL IN BANJO.

Tom Endy

[Neil Mylar LakewoodCA]

If the rear end has an offset drain plug, you an jack up and turn one wheel, while someone shines a flashlight in the drain hole to look for broken teeth. Good idea to drain oil first.

[Mitch//pa]

Originally Posted by Neil Mylar LakewoodCA

If the rear end has an offset drain plug, you an jack up and turn one wheel, while someone shines a flashlight in the drain hole to look for broken teeth. Good idea to drain oil first.

good idea

[Neil Mylar LakewoodCA]

Sorry Mitch, i overlooked your previous suggestion.