Sudden Lock Up
 

I backed up my driveway, turned the wheel to make me straight...moved forwarded in first at a very slow speed and BANG!!! the car stopped. I was shocked to say the least, I tried going forward but it was like the brakes were on. I backed up only about two feet. Then shifted into first... the old gal went forward about 50 feet and BANG and locked up.

Long story short... It kept doing this...so I stopped backing up. I jacked up the rear wheels and the right side was stuck solid. As soon as I turned it backwards it released.

I pulled the right drum and don't see any problems. The car is currently on jack stands. I ran it through the gears up to 45 MPH and in reverse. Never had a problem with the old gal.....

While it was on stands and in gear I stopped each wheel and the other took over. Shifted it through three gears..... Your thoughts...?

Re: Sudden Lock Up
 

Have you tried to adjust the brake rods per the red book?

Curious are the stands under the axles or the frame? I could see that if they are under the frame that would alter the brake adjustments because that would bend the frame.

Re: Sudden Lock Up
 

Sounds to me like you're up for a diff rebuild.

Re: Sudden Lock Up
 

Could be a broken ring or pinion gear, hopefully not

Re: Sudden Lock Up
 

Drain oil from differential. Run a magnet through it to see if there are any metal particles. You could also run the oil through a milk filter.

Re: Sudden Lock Up
 

What does BANG mean ? It just wouldn't move , or, it came to a stop with a BANG ?

It could be a side gear issue or maybe even a brake adjustment issue as mentioned.

Re: Sudden Lock Up
 

Emergency brake??

Re: Sudden Lock Up
 

Do you have a stock transmission or a T-5?

Just had a similar issue with a T-5 conversion. Rear radius rods broke which allowed the rear axle to rotate. As the rear axle was trying to rotate, the brake rods were being pulled thus activating the brakes.

Re: Sudden Lock Up
 

It’s all guesses till you spot the root cause.. metal check oil first, Inspect brakes second..

Re: Sudden Lock Up
 

Sounds like a transmission problem, pull the shifter tower, borrow a good known tower and give it a try. If you where closer I have a good tower you could use.

Re: Sudden Lock Up
 

Broken ring or pinion gears. Looks like you are in for a rebuild.

Re: Sudden Lock Up
 

Irjones, post #7, has a good point. The emergency brake bracket that holds the shoe can break causing the emergency brake to lock up. You might try taking the shoe off and inspecting the bracket.

Re: Sudden Lock Up
 

I'd say something jammed in between two gears either in the transmission or rear axle. When reversing the motion, whatever is doing the jamming is being pushed back out of the teeth contact. It could be a broken tooth or is could be some other broken part.

Check easiest first which would be a transmission shift tower removal after a check of brake components. A person can remove the left axle housing and pull the whole drive axle & differential out to check but that is a good chunk of work more than checking the transmission.

You may get lucky with this happening at low speed movement. Some angel is watching out for you. At high speed, this would be catastrophic.

Re: Sudden Lock Up
 

I agree, happened to me years back thought it was brakes( NOT) Broken teeth in rear end! as states pull plug and fish with magnet see what you fish out.

Re: Sudden Lock Up
 

I would say your ebrake lining has broken loose and is jamming in revers

Re: Sudden Lock Up
 

UPDATE: First thanks for the help and suggestions. The entire brake system is new in 2014 including everything.....the car is on jack stands under the axle...Shift Tower was rebuilt by vendor in 2015...3,000 miles on that. Always change oils in everything. Long story short... I inspected the entire undercarriage (as you guys suggested).... no problems, brakes..no problems...SO I DRAINED the differential...PROBLEM... metal flakes on a magnet and when wiped off it looked like I painted my finger silver. Probably not normal...?? I'm a shade tree mechanic...but I suspect that is too much. I guess the rear is shot.

Rotor wrench: How true....We drive the car...to Gettysburg, and Morgantown...hours and miles....I ain't upset at all....glad she took a crap locally...great!

Re: Sudden Lock Up
 

Keep fishing to make sure no big chunks of teeth in there! if not you may be lucky! I had big pieces that was being picked up when backing up and then drops when going forward. Keep us posted.

Re: Sudden Lock Up
 

Full instructions for repair of the rear end are here: https://www.santaanitaas.org/wp-cont...vised-2014.pdf

Re: Sudden Lock Up
 

The metal flakes are a problem that needs to be addressed but there is at least one big chunk of something in there (most of the time a broke off tooth)
That's what makes the sudden stop of things when it's between the ring and pinion teeth. Keep going and it continues to break off more and more teeth to do more destruction and jamming up
The above link has a ton of info on the rebuilding making it easier

Re: Sudden Lock Up
 

You are going to need to rebuild the differential. It is not difficult if you are handy with tools. The download on post 18 is mine. I have rebuilt hundreds of differentials, and if you follow the directions, it will get you there. If you go on to the web site of the Santa Anita A's of Arcadia California, www.santaanitaas.org, on the home page is my name, Tom Endy, click on it and it will bring up additional differential articles.

You should replace all the bearings, races, seals, and gaskets, cost is about $400 from Bratton's. A new ring & pinion will cost about $500. More than likely everything else in the differential will be serviceable as long as the threads and keys on the axles are serviceable.

take your time with it and be sure to use a proper spring spreader when removing the rear end. That spring can be lethal.

If you need help with questions, e-mail me at [email protected]. If you lived here in Southern California, I could rebuild it for you as I have cottage industry offering that service. Labor fee is a flat $600.

Tom Endy