Positraction question

[Hoyt99]

Well, I thought I understood Positraction. I have two old Chevys with positraction, a square body Suburban and a 63 Impala. The square body Posi works as expected.

The Impala will not roll when in neutral.

It is on jack stands now, with the driveshaft disconnected, and the real wheels are locked in place, will not turn. It feels like they are mechanically locked, as opposed to a friction lock (from brakes). When I last drove it, it seemed to move fine, and the rear wheels were not locked, but I noticed that it would not roll when in N, with the engine off.

No unusal noises. I have not inspected the fluid yet.

So, is there something in the positraction unit that would cause the rear wheels to lock as described, yet allow the car to easily move under engine power? Some quirk, or characteristic, or a known problem about to happen? No additive in fluid, wrong fluid, ?..

Before I put the transmisson back in it (the reason it is on jack stands) and connect the driveshaft and hope for the best, should I bite the bullet and yank out the differential and see what there is?

What do you think? Thanks in advance.

Chip

 

[La Hot Rods]

Are the brakes holding the wheels?

 

[Iowa 409 Guy]

If it's not the brakes it's in the pig.

 

[RussC]

Most likely the brakes

 

[dakota tom]

Parking brake on?

 

[Jim Sullivan]

Unless a bearing is bad(locked) or a gear tooth broke and jammed, it would most likely be the brakes.

 

[59K9]

pull the drums and see what happens when you spin it...

 

[1958 delivery]

pull the drums and see what happens when you spin it...

I'd say they don't come off so easily

 

[59K9]

that's when you get a bigger hammer...

 

[Hoyt99]

What could possibly go wrong.......

 

[La Hot Rods]

Anything, do you know the history of the rear end?

 

[Hoyt99]

I do not know the history other than it did sit in a garage in Santa Barbara for 22 years, and that “California Car” did not mean it didn’t rust away all that time.

So, I will pull off the drums, which has to be done to get to the axles, etc I hadn’t given enough thought to it being a brake proiblem, maybe because that might be too simple...and the solid mechanical feel in the system

thanks everyone

Chip

 

[Hoyt99]

I do not know the history other than it did sit in a garage in Santa Barbara for 22 years, and that “California Car” did not mean it didn’t rust away all that time.

So, I will pull off the drums, which has to be done to get to the axles, etc I hadn’t given enough thought to it being a brake proiblem, maybe because that might be too simple...and the solid mechanical feel in the system

thanks everyone

Chip

 

[La Hot Rods]

Well sounds like the drums would be the place to start.

 

[rstreet]

I had the exact symptoms with my 62SS late last year. Well.... right rear drum was locked and backed shoes off to remove drum. Wasn’t rusted as I had another wheel cylinder leaking
Robert

 

[Fuzz1957]

Chip,

If you do pull the pumpkin, be sure to mark and count the pinion nut revolutions when taking it off. Hope it’s the brakes!

Fuzz

MAGA

 

[rstreet]

I’d jack it up and check drums. The badly leaking wheel cylinder didn’t cause the shoes to expand and bind but how the car is used at shows appears to have caused the brake adjuster to go on steroids and drastically over adjust
Robert

 

[Don Jacks]

Emergency brake cables can freeze up and cause this too so don't over look them s a potential trouble spot.I've seen that more often with stick cars than those with automatic transmissions.

 

[El Rat]

“When” you get the drums off you’ll have found the problem!

 

[Hoyt99]

Just a follow up to share that it was the rear passenger side brake drum that was sticking to the brake shoes. once I got the drum off, I inspected and cleaned it all and the wheels spin once again. I didn’t find anything amiss in the process, so it must have fixed itself while I was cleaning it all......

Thanks again everyone. Sure glad I started with the brakes instead of the differential.

Chip