Brakes sticking until jeeps warmed up

[orange150]

The brakes on my Jeep have started sticking up until it’s warmed up. I can’t quite think why that may be other than it has something to do with heat soaking the fluid.
Maybe I have an old line that’s collapsing and the warm fluid is getting by?

I did swap in hydroboost innnnnn 2018? So the fluid is at least that old.
Thoughts?

 

[LT1JEEP]

A little info on what kind of jeep and year it is would help.

 

[shawn]

did swap in hydroboost innnnnn 2018? So the fluid is at least that old.

My first guess was bad vacuum booster, but...

Define sticking. Do you have to pull up on the pedal?

 

[orange150]

My first guess was bad vacuum booster, but...

Define sticking. Do you have to pull up on the pedal?

No, they’ll drag after depressing the pedal. The pedal returns to its rest position like normal.

 

[orange150]

A little info on what kind of jeep and year it is would help.

‘82 CJ

 

[1stgenxxx]

Can you tell if it’s more than one caliper dragging?

 

[1stgenxxx]

I’d put it on jackstands overnight and then try to turn the wheels by hand in the morning to isolate the problem.

 

[orange150]

I’d put it on jackstands overnight and then try to turn the wheels by hand in the morning to isolate the problem.

I’ll try that this weekend

 

[jeepinmatt]

I’d put it on jackstands overnight and then try to turn the wheels by hand in the morning to isolate the problem.

Be careful with this. You'll look back in 5 years and wonder why it is still on jackstands.

 

[orange150]

The cylinder on the hydroboost unit that the brake pedal attaches to isn’t returning to center all the way. I pulled it back with my hand and it fixed the issue.
Now I need to figure out why it isn’t returning on its own until it warms up.

 

[orange150]

Rerouted my return lines to see if that was the culprit.

I originally had the returns T’d together with the steering box and the booster on the straight and the leg headed to the pump. When I added the cooler I just took the leg going to the pump and plumbed it to the cooler, cooler to pump.
After doing some reading it sounds like in some instances the steering return can push against the booster return and cause problems when they’re plumbed straight on the T. I also installed a PSC pump late last year and am curious if that was exacerbating the issue.

So now I have the T right off the return port on the pump, the booster is plumbed to the leg and the steering is running through the cooler and to the straight.
The ‘correct’ way to do it is to have two return ports on the reservoir… whoops. Oh well.

 

[CarolinaHD]

I used this return fitting on the pump for my 67 C50.

Hydro Boost Return To Pump Line Kit

 

[orange150]

I used this return fitting on the pump for my 67 C50.

Hydro Boost Return To Pump Line Kit

Oh thanks! I’m planning on redoing all the lines when I drop the 360 in, that will definitely help