Brakes Dragging

[halfan8]

Has anyone ever got the feeling like your rear brakes are dragging. After driving my car at highway speeds for 10 minutes the car starts to labor as though the brakes are dragging and get hot. I assume its the rears because you don't feel anything in the steering. I pulled the calipers and greased the pins, popped out the pistons and cleaned and lubed them. I also checked the xfer case fluid which was OK. These are brand new brakes that have about 250 miles on them. Any guesses?

 

[luv2rallye]

Try adjusting the parking brake shoes inside the rotors.

 

[project15]

yeah, my rear driver's side does. the rim gets hotter than the others after i drive. it also squeaks i should probably take it off and check it out before it wears down my rotor and pads. it's probably the culprit of my low gas mileage

 

[GST with PSI]

some suggestion in general about brakes:

remove the wheel and turn the rotor with your hand. it should have little resistance caused mainly by the drive line. on the rear of a fwd there should be almost no resistance at all.
resistance would likely indicate a sticking caliper or misadjusted parking brake.

if it is you parking brake adjust accordingly or replace cable ect.

if it is you caliper it is one of two things:
-sticking piston
-sticking hardware (caliper pins)

you can tell which is your problem by looking at your pads. if you inboard pad is worn and your out board pad is fine your caliper piston is sticking. replace the caliper or rebuild it. if you old caliper has a hole in the dust boot around the piston, it won't take long for it to seize if it hasn't already.

if you outboard pad is wearing and your inboard pad is fine, your caliper hardware is sticking not allowing you caliper to slide and return freely causing your pad to abnormally wear. take a wheel cylinder hone and run it through the bores that the slide bolts go into. that will ensure your bore is clean and free of rust, burs, and debris. lubricate your slides with sili glide. it's a silicon based lube used for brakes. many people use wheel bearing grease which is wrong. petroleum based products will make rubber swell. if you ever looked at the top slide bolt on the front caliper of your car, there is a little rubber ring around the end. people put wheel bearing grease in this and it swells in the caliper bore. then they wonder why the caliper won't slide anymore.

lube the back of you pads with sili glide. it'll keep your pads from squeaking.

when you compress your calipers to put in new pads, line lock the brake lines and force the fluid out of your bleeder screws. it will keep any crap in the caliper from going back into the brake system and clogging you master cylinder up. remember the rear calipers on the rear of a 1g dsm must be screwed in due to the integral parking brake caliper design.

if you bleed the system, don't compress the brake pedal all the way to the floor. just pump the pedal as far as it normally travels when driving. allowing the piston to travel farther than normal in the bore will stir up sediment if any in the master, and cause it to be pumped into the brake system. also it's not good for the master cylinder cup seals.

if your brake fluid is brown flush it out. dirty brake fluid is hard on seals.

lube any contact points with sili glide.

this stuff if followed will really allow you brake system to work properly, and preserve all the components.

hope this helps.

 

[1993TalonTsiAWD]

some suggestion in general about brakes:

remove the wheel and turn the rotor with your hand. it should have little resistance caused mainly by the drive line. on the rear of a fwd there should be almost no resistance at all.
resistance would likely indicate a sticking caliper or misadjusted parking brake.

if it is you parking brake adjust accordingly or replace cable ect.

if it is you caliper it is one of two things:
-sticking piston
-sticking hardware (caliper pins)

you can tell which is your problem by looking at your pads. if you inboard pad is worn and your out board pad is fine your caliper piston is sticking. replace the caliper or rebuild it. if you old caliper has a hole in the dust boot around the piston, it won't take long for it to seize if it hasn't already.

if you outboard pad is wearing and your inboard pad is fine, your caliper hardware is sticking not allowing you caliper to slide and return freely causing your pad to abnormally wear. take a wheel cylinder hone and run it through the bores that the slide bolts go into. that will ensure your bore is clean and free of rust, burs, and debris. lubricate your slides with sili glide. it's a silicon based lube used for brakes. many people use wheel bearing grease which is wrong. petroleum based products will make rubber swell. if you ever looked at the top slide bolt on the front caliper of your car, there is a little rubber ring around the end. people put wheel bearing grease in this and it swells in the caliper bore. then they wonder why the caliper won't slide anymore.

lube the back of you pads with sili glide. it'll keep your pads from squeaking.

when you compress your calipers to put in new pads, line lock the brake lines and force the fluid out of your bleeder screws. it will keep any crap in the caliper from going back into the brake system and clogging you master cylinder up. remember the rear calipers on the rear of a 1g dsm must be screwed in due to the integral parking brake caliper design.

if you bleed the system, don't compress the brake pedal all the way to the floor. just pump the pedal as far as it normally travels when driving. allowing the piston to travel farther than normal in the bore will stir up sediment if any in the master, and cause it to be pumped into the brake system. also it's not good for the master cylinder cup seals.

if your brake fluid is brown flush it out. dirty brake fluid is hard on seals.

lube any contact points with sili glide.

this stuff if followed will really allow you brake system to work properly, and preserve all the components.

hope this helps.

This is so wrong were did you learn this UTI.

Just messing, nice work. sounds word for word what we learned in class you get a few points for this one, also looking forward to that pull tomarrow night.


Derek

 

[halfan8]

Just an update. I took apart the rear brakes and inspected the parking brake assembly.....it was free and properly adjusted. I did however notice that when I went to bolt the caliper back on there was a space of about 20 thou that the caliper "cage" would have to pull the caliper assembly in toward the mounting bracket in order to tighten everything up. I attributed this to the lack of a dust shield caused by using the caliper relocation brackets. Now I realize that the brakes are a full floating assembly, but with brand new pads and rotors the piston will be pushed in to its maximum postion. Would this increased inward pull of that gap possibly be pulling the caliper beyond its allowable neutral position with new brakes? This is hard to explain but I guess the jest is.....would moving the caliper in or out 20 thou have an effect on pad position enough to cause the inboard or outboard pad to drag? As a means for experimentation I made some thin shim washers to put in that would simulate the presence of a dust shield. I'm not sure if its coincidental or not, but the rotors spin a lot more free with this in place.

So after doing the shimming process I went for another ride......still no good. Up to this point I assumed it would be the rears because of the added complexity of the parking brake and because my car sat so long with no fluid in the the lines going to the rear which could have caused corrosion. I was wrong! After only a short jaunt down the road I started to feel the dragging sensation again, soon followed by the hard yet ineffective pedal feel of hot brakes. I turned around and went home, jacked the car up in the front and I couldn't even spin the wheels. I jacked the back up and the wheels would spin freely.

So, I guess its the fronts. It seems odd to me that both front brake assemblies would be corroded/seized/hung and not feel a pull to either side when braking. They both suffer the same problem with equal affects. WTF! The only thing that would be consistent from side to side is a mechanical fit or locating problem. Would the lack of a dust cover have any affect on the caliper position? I will pull the calipers off today and lube the pins and pop out the pistons for cleaning and inspection.

Thanks for the help so far!

 

[1993TalonTsiAWD]

If the front brakes are locking up,dragging, check the condition of the calipers. If there ok, check the compensating ports in the master cylinder. If there clogged, you can have both fronts lock up. Also, as far as I know about brakes I would say 20 thousandths is a bit much, they should almost rub the rotor, was there shims with the pads you installed? There should be, they can also be built into the back of the pad.

Let us know on these points and we'll go from there


Derek

 

[halfan8]

Well I pulled the calipers off the front for inspection. The pin grease was pretty dry and cruddy so I cleaned them and lubed them with the appropriate grease. I didn't actually disassemble the calipers but with the pads out I cycled the brake pedal to force out the pistons in an effort to find one that was seized.....none were found. As far as the master cylinder goes it is brand new.....I would expect it to be OK. The fluid is also fresh.

Once again I put everything back together and went for a ride......still no go. After only 2 miles at 50 on cruise control I watched the vacuum gage creep from vacuum to boost on a flat surface.

I ordered a set of front calipers (remans.) I should have them tomorrow and I will start all over again. Weird thing though......a caliper rebuild kit only has boots and seals, no pins or grommets.

 

[1993TalonTsiAWD]

How are the pads wearing? And yes a rebuild caliper kits doesn't come with the pins,etc.. thats a hardware kit, but the remain kit should hopefully work for you. How did the piston boots look? Also I know the fluid is new, but it wouldn't hurt to flush it again, although it's probably ok.

Just give a little more info on that and we'll go from there.


Derek

Also for furture jobs a loaded caliper comes with the brackets, hardware, and pads.

 

[luv2rallye]

Did you check the proportioning valve: http://www.mckeone.net/vfaq/abs/images/abs2.jpg? It rarely goes but if it gets stuck, wierd things can happen with your brakes (like all force to one side or to just fronts, etc.). Maybe it is getting stuck only when pressing hard on the brake pedal and then it holds the force on the fronts locking them up. If you checked everything and are still completely stumped check it. Usually just tapping on it with a hammer will free it if its stuck.

Supposedly there was a TSB for it on the 95 AWDs:
96-35-001 JAN 96 Rear Disc Brake/Proportioning Valve - Revision
If you follow the brake lines from the master cylinder or booster you should find it. It's usually on the firewall. It basically controls how much pressure goes to each brake, giving more to the front than the back typically. Not sure if that device is causing your problem or not, but it may be worth just tapping it since that is so easy.

 

[halfan8]

The proportioning valve is brand new. Actually, the way it is set up on these cars is a little different than the way you usually see them. There is no real pressure reference to the front brakes. The valve has 2 spring loaded shuttles in it.....one for each side of the rear. When system pressure rises to a certain point it starts to push the shuttles open and apply the rear brakes. There are only 4 lines.....L/R in and L/R out for the rears only. There are no lines in for the fronts. It would be nice if there was some adjustability, my car acts nose heavy in hard braking.......when they work HA!

 

[halfan8]

Here are my updates. I took the calipers the front calipers off and replaced them with remains. I put new pins in and greased everything up real well. Went for a ride and guess what..............STILL no good. After I pulled into my driveway, I jacked the car up from both ends. It feels like all 4 brakes are dragging. They all get hot and they can barely be turned by had after this happens. I am starting to think its my new master cylinder.

Just to recap: I have removed and cleaned/lubed the rear calipers.....including pulling out the pistons and lubing them, I have rebuilt front calipers and lubed all the sliding parts, I have checked and adjusted the parking brake, I have a brand new master cylinder (reman.), I have a new proportioning valve, My brake pedal endplay has been checked and meets the requirements of the manual, My vacuum assist check valve is working correctly to what the manual asks, My brake booster is working according to what the manual asks for, I know my return lines to the reservoir are clear as it will draw fluid fine when I bleed everything, The brake fluid is new and clean, My pad wear for the most part is even (for the wear I have seen in 2 tanks of gas) ..................all I can say is WTF!

 

[1993TalonTsiAWD]

Never assume a new part is working right. Try a new master cylinder, and go from there. Also all disk cars don't have a proportioning valve. It's a junction box.

Derek

 

[steve]

Also all disk cars don't have a proportioning valve. It's a junction box.

What?

Steve

 

[1993TalonTsiAWD]

Sorry there on our cars to. I don't know what I was thinking when I wrote that.

Thanks for pointing it out.


Derek

 

[turboglenn]

I know this post is old, but one thing i didn't see anyone mention is the adjustment of the rod from brake pedal to master cylinder.

If if doesn't let the master piston return enough the brakes will heat and fluid will expand clamping them down.

When i swapped to auto trans in my 1g i swapped the pedal assemblies and all and i had this very thing happen, within 15 miles on the freeway the car got to where the brakes pulled it down hard and i had to pull over and back off the adjuster rod on the pedal