2nd Gen Non-Engine/Transmission What would cause a brake caliper to lockup or hold the brakes on?

[GOT-Torque]

I will admit this is not on my dodge, however the question could apply just as well. Yesterday, the wife came home in the excursion, and the drivers rear brake was smoking Brake was applied on this rotor only, everything was very hot and smoking, smelled like you would think it would.



My question is why would a brake caliper hang up? Would it be due to rust around the piston in the caliper?



Any other possibilities?



It wasn't the parking brake, its never used as the vehicle is an automatic. Rotor looks like it needs replaced now as well.



Thoughts?

 

[WDixon27]

i work on euro cars for a living so this may or may not apply to a ford, i've seen abs pump/valve assemblys act like a check valve and hold pressure on a single wheel and i've seen brake hoses collaps internally and hold pressure, when i get a car doing this i get it so it's holding the pressure and start cracking fittings one at a time all of the way up to the master cylinder starting at the bleed nipple till i find the blockage, loosening a fitting releaves the pressure and you go and stomp the brake to build pressure again and try one higher in the system till you find a spot where the pressure holds in the caliper

 

[SFrey]

check your caliper slides, they rust up under the rubber boot and make the slide tight.



scot

 

[jelag]

The 2 most common problems for brake piston problems are as follows...

1 - as mentioned above by sfrey..... caliper slides
2 - the most common problem is dirt under the piston to caliper boot... this boot keeps the dirt from getting around the seal between the caliper and piston... . dirt in this are will not let the piston retract... . hyd pressure will force out the piston to stop the truck but when you release the pressure the piston will not retract... .

Look to see if the boot is pulled away, rotted or damaged in any way. . if so you need to overhaul the calipers... if there is damage to the piston... . chrome is damaged or the plastic style pistons has any scratch marks or pits scrap them and put in new ones with new kits... .

 

[JFaughn]

Being the rears , my 1st guess would be the parking brake / cable , or how ever they work on that truck .
then move on to the hyd. system .

 

[WestTN]

We bought a new 1992 Crown Vic in late 1991. At 13,000 miles the front brakes burned up. I found the phenolic brake pistons poorly machined and cracked. About 2,000 miles later, the same story on the back. Both times I installed steel pistons and didn't have any more trouble.

 

[GOT-Torque]

Would any parts store carry rebuild kits for these things? Or would it be a dealer only item? It uses twin piston calipers in the rear.



When I bought the excursion, I put brakes on all four corners and I noticed that this same caliper had the best looking pads on it. Almost new, I thought why in the world would one side be new and the other worn out. Apparently they had this problem before and didn't properly fix it.



I'll take it apart tonight and report back.



Thanks!

 

[jelag]

Two points to add... .

WestTN thanks for the spelling of phenolic pistons... for the life of me I couldn't get it right this morning... In all most all cases of piston failure... . the cause is dirt behind the protective boot... . once the piston sticks and drags, it will burn up and crack the phenolic pistions.....

Parts are available on the shelf..... here in our town we carry them as well as several of our competitors.....

One last point, never push the dirty brake fluid back to the master cylinder... always open the bleeder and let the dirty fluid go to the ground or catch container... and install fresh fluid when you bleed the system.....

 

[DJAustin]

reply-brake stuck

On my F350 it was the brake hose- it had collapsed internally and held pressure causing the brake to remain on.

 

[MistaMike]

With the left rear jacked up (trans in N) try to spin. If it does spin, pump the brakes to make the L/R "lock". Open the bleeder, if fluid shoots out and wheel spins freely then it's a brake hose. If fluid trickles out and still does not spin then it needs a caliper.



If it needs a caliper get one with the caliper bracket. A few $ more but you will not need to deal with freeing up sliders and grinding rust off the pad saddles.

 

[GOT-Torque]

Sliders were good, it was the caliper. One of the two pistons was stuck. With the caliper off the truck (but still attached to the brake line), only one piston moved with I pressed the brake pedel. So I clamped that piston in place to prevent it from moving and pressed the pedal again. Had to push as hard as I could to get the other piston to barely move. Called a few parts stores, no rebuild kits were available so I ordered a new caliper and should have it today.



Thanks for the info, I like the idea of forcing the old fluid out the bleeder and adding new fuild when bleeding the brakes.

 

[fox]

I have also seen pads wear faster on the trailing side than the leading side. As much as . 125. This binds the piston in its bore and it cannot retract.

 

[lrox]

Glad you found the problem with the caliper. One common problem on those trucks is the caliper slides ( which you have been told alot in this post) BUT dont overlook a frozen pad in the caliper bracket. Make sure the pads move freely, if not remove them and the S. S. shims and clean under them. GOODLUCK

 

[GCULP]

you may have already checked, but how does the other side look, and, isn't it best to replace brake parts in left and right pairs? a little costly maybe, but might be worth the piece of mind with the Misses.