Brake question

[azeus17]

I recently bought this Jeep. It was a manual disc/drum set up. My wife did not feel comfortable with the manual brakes, so I added a booster with a new master cylinder. Even before the booster, it would pull to the left when you hit the brakes. With the booster, it does so even more. Now, however, the front left is sticking and pulling to the left when not on the brakes and heating up, so much so I had to pull over.

I pulled the calipers all apart yesterday and greased everything up, but it did not make a difference. Spun freely when I put it together but after a test drive, it was pulling and heating up again.

Any thoughts on what do do next? Do I just need new calipers? They look original to me.

 

[Torxhead]

From your description, it sounds like a possible collapsed flexible brake line on the left side. When flexible brake lines get old they do tend to swell up on the inside making it slow to release fluid.

 

[mtnwhlr]

Sounds to me like you need to replace that caliper. Thats how they act when worn out.

 

[Old Dog]

could be either of the above.

 

[dlmalone81201]

I found out with my old grand am that if you are having problems with your left break it is a collapsed line on the right side.

Sent from my DROID RAZR using Tapatalk 2

 

[azeus17]

Thanks for the thoughts, guys. Seeing the calipers are so cheap at Advanced, I will just go ahead and replace them along with new lines.

I measured my rear drums and it seems they are the 11". Was this a mid year change or something? Why two different drum sizes and why does it effect the front calipers?

 

[BajaEdition]

I do not know the reason for the you 78 having 2 different sizes but rear brakes should be smaller than front brakes if they are different. You want the front to do the braking a vehicle that the rear brakes more will soon be going backward as the rear will try to come around. that is why they have proportioning valves.

you have to remember that jeeps are like lego sets and a lot of previous owners could have done a lot of stuff, and most of them did things without researching how it should be done. If an axle got swapped most guys do not even think about brakes, just hook up the ones on the new axle.

 

[azeus17]

Alright, I replaced the calipers and lines and bled it again. Took for a test drive (not a long enough one to really heat the brakes up too much) and the pulling seems to have gone away while braking...good news. The booster seems to be working well as I am now able to lock up all four wheels on dry pavement. When I got back, just to check everything, I jacked it up again and spun the wheel that was dragging before. It spins, but with the hardest spin I could give it by hand, it would stop within about half a turn. Is that normal? I know there will always be a little drag, but that seems to be a lot and probably enough to really heat the brake up again on a longer drive.

 

[BajaEdition]

check your bearings

 

[paparooster]

Spun freely when I put it together but after a test drive, it was pulling and heating up again .

check your bearings

When I put my hubs and bearings back on after greasing them I put the tire on with 3 lugs and then tighten up bearings while checking for bearing wobble and drag . Seeing how you just did calipers and pad , might also want to turn rotors and the you got a new brake job up front good to go for while then .

 

[azeus17]

Here's another question. When I replaced the MC, it required me to switch the lines because of the fitting sizes. I had to move the line from the back to the front and visa versa. I need to crawl under it again and trace the lines, but looking back now at my problem, this does not seem to be right.

Are all MC set up the same where the front reservoir is for the front brakes and the rear for the rear brakes? Keep in mind this is a disc/drum set up. If that is the case, I would need to switch the hard lines coming out of the cylinder and use some adapters. I thought I read somewhere that the disc circuit has some valve or something the drum circuit doesn't (or maybe it was the other way around). Would that be located in the MC???

 

[mtnwhlr]

I think you have found what the problem is in your last post.

 

[Old Dog]

I think you have found what the problem is in your last post.

The bigger reservoir is for the front discs.
And yes the discs should have a 2lb. valve and the rear drums have a 10lb. valve. So switching them could cause problems.

 

[Nekator]

Well mate, have you sorted it out by now? Managed to pinpoint the problem?