91 Front Brakes Dragging

[Ghetto400]

Hey there

Quick question for all the lucky LS owners. I have a 91 LS that feels like it is braking all the time. I changed the pads and rotors the other day and the master cylinder last year. the front brakes are getting way too hot and are smoking when i stop and get out. When i changed the rotors and pads the individual pistons in each caliper would retract but i couldnt get both to retract at the same time when using a c-clamp on face of the pad. both sides are doing it so I dont suspect a sticking piston esspecially when they individually will retract when pushed back in. the master cyclinder is only a year old and had all new fluid when i replaced it. Anybody have this problem and fix it with maybe a part in the antilock system or proportioning valve or maybe the TRAC system. I have not sprung for the Maint manual for this thing yet and thought maybe somebody would know enough about the brakes to explain how many doo-dads are in between the master cylinder and the calipers on this over-engineered tank. (loving insult) I have half a mind to follow the lines and ditch everything in between just because it is ticking me off that bad.

PS it was doing this with the old pads and rotors so it is not the new parts either.

Thanks in advance

ghetto

[IS400]

There are these little wishbone shaped springs that fit on the pads to help them retract. Were they there when you went to change the pads? Them not being there should not cause the problem you have though IMO. Just a thought.

BTW I think the track only controls the rear brakes, if I remember correctly.

[IanRShearer]

Hey there

Quick question for all the lucky LS owners. I have a 91 LS that feels like it is braking all the time. I changed the pads and rotors the other day and the master cylinder last year. the front brakes are getting way too hot and are smoking when i stop and get out. When i changed the rotors and pads the individual pistons in each caliper would retract but i couldnt get both to retract at the same time when using a c-clamp on face of the pad. both sides are doing it so I dont suspect a sticking piston esspecially when they individually will retract when pushed back in. the master cyclinder is only a year old and had all new fluid when i replaced it. Anybody have this problem and fix it with maybe a part in the antilock system or proportioning valve or maybe the TRAC system. I have not sprung for the Maint manual for this thing yet and thought maybe somebody would know enough about the brakes to explain how many doo-dads are in between the master cylinder and the calipers on this over-engineered tank. (loving insult) I have half a mind to follow the lines and ditch everything in between just because it is ticking me off that bad.

PS it was doing this with the old pads and rotors so it is not the new parts either.

Thanks in advance

ghetto

Have you got some free play on the brake pedal, it could be the master cylinder piston is not moving back far enough to release the fluid pressure.

That's just a general thing, I don't know what the setting is for the LS

[Ghetto400]

There are these little wishbone shaped springs that fit on the pads to help them retract. Were they there when you went to change the pads? Them not being there should not cause the problem you have though IMO. Just a thought.

BTW I think the track only controls the rear brakes, if I remember correctly.

Yeah unfortunately they are...the car has been in south florida all its life and the pads did hang in the caliper a litte before i took a dremel brush and cleaned the hangars and those springs you are talking about. The springs are working but the pads are backing all the way up against the piston so im pretty sure it isnt those. the pads move back and forth nice and smooth now after the dremel business but, it still has the same issue. thanks for the input though. I found one post of somebody that has the same problem but the post just stops with no resolution...

gonna change the calipers anyway just to eliminate them as the cause and possibly order some stainless lines to eliminate the possibility of the old lines not allowing the pressure to release....calipers is probably a 50% shot in the dark and the lines are maybe a 10% chance but who knows i might get lucky... Have to drive 1K miles back to work on Wed Morning so am trying to get a resolution before i toast $300 in rotors and pads i just put in...bummer

I actually overlooked the pedal freeplay becasue my light was going out when i let up but ill go check that possibility too befoer dumping 150 in the calipers...thanks

[IanRShearer]

I actually overlooked the pedal freeplay becasue my light was going out when i let up but ill go check that possibility too befoer dumping 150 in the calipers...thanks

you could try opening a bleed nipple, if there is a spurt of fluid and the calipers release, you would know it was a fluid pressure problem.

If the free play wasn't checked when the master cyl was replaced, I say there was a good chance that's what it is.

[Ghetto400]

you could try opening a bleed nipple, if there is a spurt of fluid and the calipers release, you would know it was a fluid pressure problem.

If the free play wasn't checked when the master cyl was replaced, I say there was a good chance that's what it is.

Well I checked the free play...was also a good opportunity to hack my knuckles up and slip a disc in my back:D

Free play was good and is now better...maybe too much better. anyways...still hanging up so freeplay is out. Will go out in the AM and play with a nipple (hope my ol'lady doesnt catch me.) thanks for the idea... I thought about it earliear but wasn't in the right frame of mind watching it smoke up the driveway. Thought about pouring some gas on and watching tv and wait for the fire department to inform me of my horrific loss...

Love the car but hate uncovering new items to put on the laundry list of stuff everytime i turn a wrench to try and make things better. Ohh well...its 18 years old. gotta expect it.

Ghetto

[TexasLexus94]

I changed my pads and rotors about a year ago, and when I pulled into a casino garage, there was a ton of smoke coming from the front brakes. So I asked my mechanic here in Vegas if I had screwed something up. He said "No", that the smoke would go away shortly. And he was right. And my brakes work perfectly now. Hopefully you just have a "settling in" problem. Sure worked for me.. Best of luck.

[curiousB]

If you have a sticky caliper it seems somehwt unlikely more than one would develop this problem at the same time. Did you mean to say both right and left front were hot? Since you say the pads and rotors were new it doesn't sound like a bedding in thing as there wouldn't be too much surface variance with all new. I don't think this is normal nor do I suspect it will just go away.

I guess if the old pads were pretty worn the pistons were extended for a long period of time. If moisture got behind the seal that part of the piston could have had some rust and corrosion. Now that it has been pushed back into the caliper it could be binding some. This would have the effect of not allowing the pistons to fully release after you let off the brake. In effect would keep a constant drag on brakes and coud explain the heating you are seeing.

It might be a lot cheaper to get a caliper rebuild kit. Take out the piston clean them up and then restore all with new seals and o rings. A bit of work but a lot cheaper than new calipers. Depends if you've got the time to just into this minutia.

[Ghetto400]

If you have a sticky caliper it seems somehwt unlikely more than one would develop this problem at the same time. Did you mean to say both right and left front were hot? Since you say the pads and rotors were new it doesn't sound like a bedding in thing as there wouldn't be too much surface variance with all new. I don't think this is normal nor do I suspect it will just go away.

I dont think it is bedding in either...No offense to the poster before and many ideas are always better than one but, I have changed plenty of pads and rotors on cars bikes trucks and even a plane or two...if you clean your new rotors with brake cleaner before you replace there is almost no smoke. If you leave the anti rust coating on them that they put on so you dont have a heart attack when you open the box then it will smoke...but thanks for the input.

I guess if the old pads were pretty worn the pistons were extended for a long period of time. If moisture got behind the seal that part of the piston could have had some rust and corrosion. Now that it has been pushed back into the caliper it could be binding some. This would have the effect of not allowing the pistons to fully release after you let off the brake. In effect would keep a constant drag on brakes and coud explain the heating you are seeing.

It might be a lot cheaper to get a caliper rebuild kit. Take out the piston clean them up and then restore all with new seals and o rings. A bit of work but a lot cheaper than new calipers. Depends if you've got the time to just into this minutia.

Well the reason all this started was that i changed all the bushes in the front due to clucnking and steering wobble etc... I had put new pads on but no rotors last year when my master cylinder went !Removed! up. when i took front end apart to do bushes i noticed that the pads were very worn already after only about 5K miles ive driven it since last year. So im pretty sure it was doing it to some extent the whole time but not bad enough to really get my attention. When i put the new pads and rotors on yesterday it was a drastic difference the drag was immediately noticeable and as i said they were smoking and i felt the wheel and it was too hot to leave my hand on...THE WHEEL was too hot... OUCH! As for the "both" statement. Both sides are doing it so you are right in suspecting someting that affects both sides. It is in the back of my mind too.

When i was talking about the pistons in the calipers i could get one piston at a time to retract (brake pad see-sawing) but not both pistons to retract at same time in the same caliper. Thats why i had the question about something (anti lock TRAC etc..) in between stoppping flow from returning to Master Cylinder. As for the Rebuild kit...I do understand it is cheaper but i just dont have the time before i bail for work on Tuesday so the calipers are a 30 minute job vs a couple of hours or more cleaning pistons and and replacing seals. Besides the calipers come with all new springs and carriers so after 198K on these l think she could use some new ones. What a needy Bit__! Ha!

Ghetto

[curiousB]

I agree swapping calipers is a safer repair. Less time, fewer variables to contend with. You're also certain the calipers will be properly functioning. Sounds like you should flush old brake fluid before you put in new calipers. There might be some crud in the lines. You don't want to contaminate the new calipers. When you look what a rebuilder does to remanufacture a caliper its seems a pretty good deal for $80-100 or so a side.

• - All units are disassembled down to the casing and steel shot blasted to ensure a thorough cleaning.
  
• - Only original equipment type cores are used in the rebuilding process.
  
• - All threads are inspected and tapped. Only new bleeder screws and copper washers are used.
  
• - All casting bores and seal surfaces are tested and inspected before assembly to prevent leaking and ensure a proper fit.
  
• - All steel pistons are tested and inspected for roundness, pitting and cracking. All good steel pistons are refurbished. Defective steel pistons are replaced with new ISO 9002 Certified steel pistons.
  
• - All phenolic pistons are replaced.
  
• - All units are assembled with new ISO 9002 Certified rubber components that meet or exceed O.E. and S.A.E. standards and with the highest quality assembly fluid and silicone grease.
  
• - All caliper ear hardware (rubber bushings and slider sleeves) are installed.
  
• - All units are tested after assembly and run through a quality assurance program.
  
• - Hardware (bolts, clips, sleeves, springs and rubber components) and Brackets are supplied and mounted where applicable.
  
• - All threads are inspected and tapped. Only new bleeder screws and copper washers are used.
  
• - All calipers are individually shrink wrapped before boxing to ensure high quality and trouble free product.