[guinnburger]

Just rebuilt the 400 in my '78 Trans Am, ('71 ram air engine with 400 tranny).
For some ding dang reason I can't do the normal thing you do when you are working on your car and need to push it in the garage at night, turn the key on, put it in neutral and push. I've been rebuilding these things for a hundred years and never run in to this. I've checked the parking brake, loosened it just to be sure, went through all the shift points on the transmission to make sure I wasn't in a locked gear, none of the shocks have jumped out of the slot to bind the wheel. (It has rear drum brakes with good pads).

The only thing I can think of is that I haven't had any part of the car greased anywhere in a long looong time, and don't even know if one greases a wheel/brake assembly. What else could possibly be binding to make the car not roll?

The irony is that it's running better than ever, I can only imagine what it would do if something was not compromising it's ability to roll well.

By the way, I also noticed something I didn't know before. When the rear end is lifted on a jack and you turn a rear tire forward, both wheels go forward. But if you turn one backward, the other one turns the opposite direction (forward). I will never understand limited slip differential.

Joey

[Jeff Walker]

You might have a front brake caliper that might be hanging up.
JAT

[Region Warrior]

Brake cable frozon?
Shoe or shoes not releasing in a drum?

Raise up one end at a time and check if all wheels are free.

[guinnburger]

Damn, you're "Jeff on the Spot" how did you get that before I hardly sent it?
How would I check the front caliper?

[guinnburger]

Oh, 10.10 @ 131! that's how your so fast. What do y'all think about the opposing wheel rotation deal I mentioned? Joey

[Jeff Walker]

Originally Posted by guinnburger

Oh, 10.10 @ 131! that's how your so fast. What do y'all think about the opposing wheel rotation deal I mentioned? Joey

LOL That's funny

Probably a tired stock posi unit. Do like Pochoshop said. Check one wheel at a time and you'll probably find it. If it's one of the fron ones that is hanging up, loosen up your caliper and pry it back a bit. If it turns free you found the problem.

BTW if it is that and you need to replace the caliper, get both sides right away. If one side is hanging up it's only a matter of time until the other side does.

[guinnburger]

It was probably a subtile warning when I got a new front tire last week and the tire dude broke off a lug bolt, so new calipers are in order anyway.
Thanks again for your time replying to random stuff, this forum sure would have been handy back when I was trying to communicate Pontiac stuff with Ford and Chevy addicts. peace

[carcollector]

As mentioned above, that can most definitely be the first sign of trouble with a posi unit. It happened to me years ago.
Whatever you do, don't ignore it.
Chris.

[guinnburger]

Chris, let me understand this. If a posi unit is going kaput the rear wheels will turn in opposite directions when either one is turned by hand? That's down right weird. I'm thirsty now.

Joey

[242177P]

You aren't using rims that contact the caliper, are you?

[guinnburger]

No, just the stock snowflake Trans Am rims. I still can't imagine why one rear wheel would rotate the opposite way of the other when it's up off the ground.
As far as something binding, I have not checked the bearings yet, if they are worn out I quess that could cause binding. I hate to admit it, but I've spent so much time and sweat learning how to overhaul and tweak engines, that I've never figured out basic stuff like brakes. I'm the guy who goes to a car dealership and asks some clueless salesman what rear gear is in a new GTO, then I listen to him explain to some other customer all about the stereo system and chrome plated rims. yep

[78 GHOST]

Guinn:

Don't forget the tire pressure, even a bit low makes it a bear to push. The 78 TA is a hog, super heavy.. I can one hand my GTO rolling chassis up the driveway or up a trailer. I could not do that with a TA.

As to wheel bearings, there is definately a point where you're too tight. If I recall correctly, I heavily grease up the bearings, install the rotor with the spindle nut just barely snug, then put on a wheel with only a couple of lug nuts tight enough to prevent any wheel to rotor slop. Then I spin the wheel and tighten the spindle nut until it's just tight, then go another 1/4 -1/2 turn while still turning the wheel (this seats the bearings.) Next, back off the spindle nut and repeat the procedure but stop when the nut just becomes tight, then back off 1/2 turn and lock into place with a cotter key, only back off the nut to align the cotter key with a hole. Be careful not to overdo the seating procedure as it's super easy to damage a caged taper bearing. Again, you want to err on the loose side. Ideally, you should be able to grab the wheel top and bottom and see a little bit of wobble, imagine .030-.040" worth of play.. barely perceptible. Getting bearings too tight ensures an early failure, and a costly repair.

I'd also check to ensure you have the U-Joints properly lubed, and that you're not binding anywhere.

[guinnburger]

Very useful info Ghost, thanks a lot. I've got plenty to go on now. By the way, I've also got a wreaked '81 T/A that I'm considering swapping out the whole rear end with the '78 so it will have rear disc brakes. Do you see any unforseen pitfalls with that?

[78 GHOST]

Nope, that is a great swap. Just keep in mind that you will need to swap the Master Cylinder, and the proportioning valve to ensure proper function. If you've got the old car, just take everything brake related and put it on your car and you should be all set.

The Master Cylinder for the Disc/Drum setup and the proportioning valve are different than the Disc/Disc setup. In fact, you might even use the hard lines from the '81 to connect the M/C to the Proportioning valve and the rear hard lines.

[ChrisTransAm78]

Jack it up and turn the wheels to finding offending one ?

[Thumpin455_GTO]

Just a bit of info.. If you have a caliper hanging up, change out the brake lines with the calipers or when you rebuild a caliper. Often the brake line has a split in it that acts as a one way valve, it will apply but not release untill it leaks down.

How long has it been since the brake lines on your car were replaced?

[guinnburger]

The brake lines replaced, hmm lets see....The cars a 1978 so I guess that would be 28 years. yep

[Philcol]

Did you rebuild the front end? Alignment does have have to be off much to make one hard to roll. I have first hand experience on this.

Phil

[guinnburger]

Phil, three things.
(1.) yes I did rebuild the front end (new tie rods, new sway bar support bushings, etc.)
(2.) You are absolutlely right, when both front tires are pointing different directions it does make for a hard dinner roll, which by the way was the problem.
(3.) I answered my own question about why one rear tire turned the opposite way of the other when it was up on a jack. I noticed nobody really answered me back about that. Probably because nobody snapped that when the car is in park it is kept from moving by reversing the direction in which each wheel turns, if one goes forward and one goes backwards, it can't go very much anywhere. I swear I didn't know that.
(4.) Oh! that's four things...oh well. I was intriqued by your little dealy deal about "dreaming I was awake , and waking up sound asleep," that is so much like my dream within a dream. If you want to read something dumb read my post in "Your Best Pontiac Stories," and click on "Trans Am Lucid Dreams."
peace, Joey

[Region Warrior]

#3

As long as both turn, even opposite directions, thats not your problem.