Gen 2 Brakes sticking

[Mack302]

I've tried to look around to see if this has been discussed before but I've had little to no luck. I picked up a 92 SHO at the beginning of the year and I always noticed that after driving for around 15-20 miles then the brakes seem to stick. I have to physically pull the brake pedal up with my foot to get them to release for the remainder of the day, but that still doesn't seem to fully release the brakes. (It seems to reset by the next day)

I lifted the car up when it was giving me issues and it was definitely both front wheels because I could not spin the wheels while the car was in the air and in neutral.

I have already changed the master cylinder and the front brake calipers to brand new parts. At first I thought that had corrected the issue, but it is back. I've ordered new rubber brake lines for all 4 corners but other than that I'm not sure what to do

I would love some advice! Thank you in advance

 

[Irish Pride]

The rubber brake lines could very well be the issue. When they get old they will break down internally and restrict back flow from the caliper. Try those first.

-Chad

 

[sperold]

This^^^^^^.
Very common on the back brakes as the flex line has a retainer ring that makes the situation worse.

If you feel your front rims after your drive, they are probably hot, compared to your rear rims.

 

[luigisho]

rubber hose first and highly likely, maybe caliper failing second, and then even less likely stuff from there. report your success/fail on what you find out

 

[SHOrod]

With the front wheels in the state where you're unable to spin them freely, jack the vehicle up and safely support the car. Remove the front wheels, then open the bleeder screw for a second or two, close the bleeder, and see if you can now freely rotate the axle. If so, that's a pretty good indication that the caliper is not the issue and the most likely issue is the brake hose.

-Rod

 

[Mack302]

This^^^^^^.
Very common on the back brakes as the flex line has a retainer ring that makes the situation worse.

If you feel your front rims after your drive, they are probably hot, compared to your rear rims.

Yes the front rims are hot after a drive when compared to the reara

 

[Mack302]

I've changed all 4 rubber brake lines but no luck.

So now the car has:
- New Master Cylinder
- New Front Calipers
- New rubber brake lines at all 4 corners

No improvement. Same issue. Roughly 30 mins of driving and the brakes stick again and require me to manually lift the pedal to release the brakes.

 

[zoomlater]

Maybe the brake booster, in the last post, Rubydist also pointed out the possible issue with the hard brake lines

Front brakes dragging and smoking

had a first time experienced yesterday when I noticed the car started slowing down and losing power as I was tryna give it more gas, I went to mash the brakes and the pedal was real tight, I threw it in 1st and the car went nowhere and the front brake began to start smoking on both sides I let...

shoforum.com

 

[yaycandy]

Ive had that issue a couple times on 90s vehicles. And all of it was the abs box, either not being bled correctly or something sticking in it. Replace literally everything on the brakes and still have the issue while driving. Pull over, crack bleeder to un jam the caliper and drive again for a bit till the next jam up.
Everytime the fix was to replace the abs box where the lines run into under the hood. One car i did and it worked well my time with it and another i couldnt find a reman unit so i made my own brake lines and jumped around the box. Oh and the abs box never puts its light on to say theres an issue when there is

Actually the pedal on both my vehicles with abs causing to much pressure would be stiff or stuck down fully locked that i had to yank up on it also. A hose wouldnt do that, you need to command alot of pressure into a larger area than a collapsed hose

All this assuming you have abs, if not than disregard my rant.

With my brakes knowledge which is more than most on 90s and older. Assuming no abs and not remembering what was said on other posts already. If the brake hoses are changed, as i think I remember reading. Than it cant be from them not being bled correctly or having air in the lines. Because then the pedal would go flat to the floor when it gets the air and not cause a lock up. Doubtful thats its a pinched hard line as i just dont see it, but ive seen worse.

Master cylinder going bad just makes no pressure and pedal to the floor no brakes. (Been there on my 70s caddy, fun times)

But you could have rust or other stuff in the brake lines that clogs up even new hoses pretty quickly. Ive seen that once already.
Now the focus is on the caliper. They can stick. Even if they are new. Rotors can be made to thick and cause pads to rub. Pads can also be installed wrong or made wrong that they hang up and stay against the rotor even when the piston goes back. It wont be a hard drag but enough to make the rim warm. A hard drag is caliper sticking hard, a collapsed or clogged line or the dam abs box.

Now that weird ass thing the rear of my 90’ has thats on a spring and releases pressure or something when the rear lifts when the front dips to avoid fishing tailing. I dont even understand it.

Oh I have the gen 1 sho abs bleeder device, got it from old beck a few years back on here. Not sure If its the same on a gen 2

Actually been restoring an 80 merc diesel we picked up recently. 1 brake worked as we drove it around roadkill style. All others rusted that they wernt even moving components anymore

 

[luigisho]

The teves bleeder is the same across GenI &II Raybestos also has the same rebranded unit. Now I would look at booster, air in lines, rear calipers (unless you know which is binding) hard lines, abs module. I would do a thorough bleed and check the booster.

 

[Paramedic Terry]

A quick check would be to unplug the vacuum hose from the booster. If this frees up the brakes, I think it would indicate either friction, or an internal leak in the booster that is pulling on the pedal and not letting it return all the way. That's the only condition where pulling back on the pedal would release brakes.