1968 Bronco Locking Brake Issue

[sundevilbronco]

Hello All,

Apologize if this is covered somewhere else but I searched around and couldn't find anything. Additionally, I just bought a 1968 Bronco to learn how to work on cars so I am still quite ignorant.

I have owned it for about 4 months and on three occasions now, I have had what I think to be a brake lock up on me but only after I drive around for a bit, turn it off and then turn it back on (think like going into a grocery store and coming out). I am able to shift into gear like normal, but the Bronco doesn't even roll when in drive unless I am pretty much slamming on the gas. It then moves, but it is very slow and I feel like I might be causing damage. Each time it has happened, I have waited a couple of hours, tried again and no issues.

I have no idea what it could be it seems like cooling it off, waiting, etc does the trick? It doesn't have an e-brake and it has disc brakes all around. Happy to provide any additional info.

Thanks so much for the help!

 

[jckkys]

So many of these trucks have been modified, it's hard to know what you have for brakes. The '68s originally had manual (non power) 4 wheel drum brakes. Is that what you have?

 

[EPB72]

Lots of possible things, poor install, mismatched parts selection..first check fluid level needs 1/4 inch air gap ,or could have max fill mark depending on MC used,if ok ..Then I think your going to have to get it to fail and determine which wheel or wheels is staying locked up by lifting off ground ..also IDing which disk brake set ups are installed would help..pictures would be nice.

 

[sundevilbronco]

That is correct, sorry for not including that earlier.

 

[gearida]

Mine will lock up at the master Cylinder if my rod length is just slightly too long between the power booster and the master Cylinder, but only after about twenty five miles or more.

 

[jckkys]

If you're new to this, I would take it to someone like Brake Masters.

 

[sundevilbronco]

I was able to get a couple pics of my brakes. I have a broken hand so I will have to wait a few weeks before I can put it on a lift and pop off the wheels.

 

[SteveL]

Does it have power brakes? Also you should be able to see if it has rotors or drums without lifting it up. Also a location. Maybe somebody will come by and help out.

 

[DirtDonk]

You'll need to upload any pictures to your "garage" or "gallery" areas of your user-CP above.
To post them directly to a discussion you would need to spend the 12 bucks (very well spent for most of us by the way) to become a contributor.
You can also send them to me at paulb@wildhorses4x4.com and I can post them for you.

If you have a vacuum brake booster though, the most common reason for your issue is what gearida said, a rod adjustment issue.
Sounds like it's been doing this since you bought it? Pictures will definitely help. That way even if you don't know what has or has not been done, being fairly new to Broncos, someone might be able to see a problem or a benefit and let you know.

Good luck. With the Bronco and the hand!

Paul

 

[stanz]

I had this before... pushrod on the master cylinder was too long causing the brakes to drag and the fluid to heat up (and expand). Immediately after stopping and sitting the brakes would lock up.

 

[blubuckaroo]

I've seen that happen when someone uses a drum brake master cylinder in a disc brake application.
Drum brake master cylinders have a residual check valve that holds a slight pressure on the system after the brakes are released. This is to keep pressure on the wheel cylinder piston cups so air and water can't get in.

 

[Jfryjfry]

Where are you located?

 

[toddz69]

I'm guessing he might be here in Phoenix if his username has any correlation to ASU?

Todd Z.