locked up both front brakes

[jeeptorino68]

looking for some ideas on help with my front brakes.
1992, 4.0 auto, 245k miles. ABS (not the crappy bendix stuff...)

was towing a small utility trailer and had my wife and a friend in the jeep, with some weekend supplies headed to seattle. there was some moderate traffic and i was into the brakes a couple times but nothing out of the ordinary or that would have seemed to cause it, then both front brakes were dragging, there jeep was hard to keep going, but i got off at an exit and into a parking lot, they were not but not spewing smoke, no discoloration etc. they would not release (both fronts, rear drums were slightly warm, but you could touch them, so i think just the fronts were stuck) so my dad came and we towed the jeep home)

about the time we are loading it on the tow dolly, the brakes seemed free (about 30 minutes after they were stuck/dragging)

he took a look at the jeep for me while we went to seattle in his truck, didnt see anything wrong and sunday we went back home with the trailer...workign fine...
i found one mention of this on jeepforum where another member with a 92 had this problem, and replaced calipers and front hoses and didnt have the problem again...

but what would cause both front calipers to drag/be stuck?

thanks

 

[8Mud]

Have you added any brake fluid lately? I got my XJ back from the dealer (one of the few times I ever took it there) and my fronts locked up a couple of days later. They had topped of my brake reservoir with water polluted brake fluid. The brakes would get hot, the moisture in the caliper cylinders would turn to steam and lock my brakes. After they cooled down everything was fine again, until the next time. It took me awhile to figure out what was happening. I finally caught on when I opened a bleeder when the brakes were hot and it blew a giant cloud of steam out of the bleeder.

May be your issue or it may not, just an idea.

 

[WB9YZU]

I've seen calipers stick before on Jeeps I don't use much, and I've always attributed it to moisture in the fluid causing the bores to rust abit.

I'd replace both front calipers, and if the hoses are as old as the Jeep, those too for good measure as old hoses can collapse and prevent the piston from retracting.

Then look at the back brakes. Make sure the shoes are up to snuff, the auto adjusters work properly, and they are properly adjusted. Neglected rear brakes force the bias towards the front, and what should be a 60/40 effort becomes a 100/0 effort.

-Rom

 

[jeeptorino68]

rear brakes are new probably 5 years ago...probably time for a check and adjustment on those i suppose...makes sense on the fluid. might get the local shop to flush the brake fluid for me. some good ideas.

thanks

 

[winterbeater]

rear brakes are new probably 5 years ago...probably time for a check and adjustment on those i suppose...makes sense on the fluid. might get the local shop to flush the brake fluid for me. some good ideas.

thanks

Look up gravity flush and do it yourself. I've posged the procedure several times in the past.

 

[O-Gauge Steamer]

Look up gravity flush and do it yourself. I've posged the procedure several times in the past.

Good way to start but.... It will take a "pressure" bleed to purge all of the fluid. Hand operated vacuum pumps are readily available in numerous locations. This is just one example:

http://www.amazon.com/Mityvac-MITMV8500-Silverline-Automotive-Vacuum/dp/B0002SQYUA/ref=sr_1_5?s=automotive&ie=UTF8&qid=1402151577&sr=1-5&keywords=brake+bleeder+kit

As it happens, that is the exact one I use. The manufacturer has other less expensive, versions as well. Here is the Amazon search page:

http://www.amazon.com/s/ref=nb_sb_ss_i_1_11?url=search-alias%3Dautomotive&field-keywords=brake%20bleeder%20kit&sprefix=brake+bleed%2Cautomotive%2C282

IMO, the best bleeders actually puts pressure into the system at the master cylinder. Those tools are always more expensive. It may well be that you can find a tool at your local tool rental place.

Maybe not but, worth a call...

 

[winterbeater]

Good way to start but.... It will take a "pressure" bleed to purge all of the fluid. Hand operated vacuum pumps are readily available in numerous locations. This is just one example:

http://www.amazon.com/Mityvac-MITMV8500-Silverline-Automotive-Vacuum/dp/B0002SQYUA/ref=sr_1_5?s=automotive&ie=UTF8&qid=1402151577&sr=1-5&keywords=brake+bleeder+kit

As it happens, that is the exact one I use. The manufacturer has other less expensive, versions as well. Here is the Amazon search page:

http://www.amazon.com/s/ref=nb_sb_ss_i_1_11?url=search-alias%3Dautomotive&field-keywords=brake%20bleeder%20kit&sprefix=brake+bleed%2Cautomotive%2C282

IMO, the best bleeders actually puts pressure into the system at the master cylinder. Those tools are always more expensive. It may well be that you can find a tool at your local tool rental place.

Maybe not but, worth a call...

Why won't gravity get it all? I've had friends have problems sucking fluid thru with mityvac. Pressure bleeder like Motive is the best if you want to spend $100.

 

[dcampbell98XJ]

It may be a little out of your price range or not but my shop uses one of these to do all of our flushes and they work great. http://www.tooltopia.com/mityvac-mv6835.aspx
On another note brake fluid does go bad. Not just moister but copper from the lines and everything else. The copper lowers the boiling point of the brake fluid and can cause it to overheat causing steam and other issues. It's always a good idea to flush the system every couple years. Or if you buy one of these flushers it only takes about 10 minutes.

 

[O-Gauge Steamer]

^^For sure the better bleeding tool by far.

As to issues with the vacuum operated unit, I can only state my experience which has been positive in nature.

In any event, a very thorough purge of the OPs brake system is, IMO, in order.

 

[winterbeater]

Purging the fluid is always good, if you don't know it was done in the last couple of years.

But it seems like steam or whatever would always be released out the master cylinder when pedal is released. I'd take off eack caliper and make sure the pistons push back in without too much effort. And look for the infamous grooves where the pads ride on the calipers. Fluid should push back up into the master.

 

[dcampbell98XJ]

You can usually tell if the system is in need of a flush by the color of the fluid in the mc. It should look pretty clear the older and more crap that gets into it the color starts to get a green tint. At my job we must use test strips on every car that comes in for even a simple look over. I'd say 7 out of every 10 cars I look at have contaminated brake fluid. Even cars that are a year or two old and recommend a flush. Takes 20 minutes if all the bleeders open.

 

[Talyn]

I made one of the pressurized style that you attach to the reservoir from a cheap garden sprayer, some hose, a barb and a stock reservoir cap. A few pumps and your ready to bleed.