ST165 front brake calipers sticking?

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ST165 front brake calipers sticking?

Postby machomateo » Sat May 30, 2015 4:10 pm

Hey all, one of my maiden posts. I usually am using the search tool for my problems, but only found a couple topics that were similar but not totally like mine, so I figure post my situation and see what kind of suggestions I get.

So.. I have an '88 ST165 with an ST185 motor/trans swap. When I got the car, the brake pedal would almost go to the floor, it stopped the car but not as good as it should, and kind of sketchy if you ask me. I tried bleeding the brakes and that made no difference so I decided to start replacing the brake system one component at a time. I started off with a rebuilt vacuum booster and a rebuilt master cylinder, bled the system correctly. Voila, spongy pedal feeling/pedal to the floor feels much better but braking power left much more to be desired. So I decided to buy new pads and rotors (pads were shot and rotors were grooved and past their wear limit.) Purchased OEM replacement rotors from RockAuto (I know, not the greatest source but it'll work), then bought EBC Reds for the rear and Porterfields for the front. I would've bought matching pads having known that EBC did not make a set of the fronts (they claim they do, but they are not the correct ones). Anyway, I install the pads and rotors, and bleed the entire system again. Go for a test drive, first press on the brakes, amazing, feels great, stops very nicely. Let off the pedal, accelerate, and step on it again, this time a little more aggressively, again stops great but this time when I let off the pedal, the front pads are dragging badly, I could barely make it home, if I hit 3rd gear the engine didn't have the power to overpower the brakes, So I decided to rebuild the front calipers. I purchased a rebuild kit from Toyota, disassembled both calipers individually, cleaned the hell out of them, replaced all the parts that came with the kit, reassembled, bled system, go for a test drive, same damn thing, dragging to the point they are smoking :bangshead: So I decide, maybe, just maybe it the Porterfield racing pads, so I order up a set of Toyota OEM for $76 from the stealership, install, bleed, test drive, SAME THING!!!
Does anyone have any idea what the hell is going on? Am I overlooking something? At this point I've rebuilt almost the whole braking system aside from the rear calipers (which are fine.) Forgot to mention, the car has stainless braided lines too, so assume thats not the problem either.. HELP PLEASE, This thing is driving me insane.
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Re: ST165 front brake calipers sticking?

Postby underscore » Sat May 30, 2015 5:44 pm

Does your car have ABS or no? Did you completely flush the brake fluid or just bleed it? Sounds like something is gummed up and not allowing the pressure to return properly.
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Re: ST165 front brake calipers sticking?

Postby machomateo » Sat May 30, 2015 6:02 pm

Car does have ABS as far as I can tell. There is a light on the dash for ABS and also a fuse, so I can only assume it has ABS. Is there another way to tell? I'd say we flushed it pretty good, I'd say we pumped and bled each caliper about 9 times a piece, seems sufficient to me. I'm thinking about removing the calipers again and just disassembling them, re-grease them, and see if that makes a difference, even though I just did that. I'm at a lost of ideas now. I could buy rebuilt calipers but I just rebuilt my own, so that seems pointless.
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Re: ST165 front brake calipers sticking?

Postby BlackDragon » Sat May 30, 2015 9:20 pm

If you are sure your calipers are up to snuff, I would replace the brake hoses. They get old just like any other rubber part and can collapse after getting hot.
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Re: ST165 front brake calipers sticking?

Postby machomateo » Sat May 30, 2015 9:26 pm

BlackDragon wrote:If you are sure your calipers are up to snuff, I would replace the brake hoses. They get old just like any other rubber part and can collapse after getting hot.



They are steel braided lines.
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Re: ST165 front brake calipers sticking?

Postby BlackDragon » Sat May 30, 2015 9:31 pm

With the caliper removed, is it hard to push the piston back in?
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Re: ST165 front brake calipers sticking?

Postby machomateo » Sat May 30, 2015 10:29 pm

BlackDragon wrote:With the caliper removed, is it hard to push the piston back in?


Yeah, more difficult than other brake systems I've worked on. But I took them both apart, cleaned the hell out of them, even used Scotch Brite, and re-assembled with the rebuild kit from Toyota. All the o-rings, rubber sleeves, seals have been replaced.
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Re: ST165 front brake calipers sticking?

Postby BlackDragon » Sat May 30, 2015 10:33 pm

If you open the bleeder, does the piston go right in or is it still hard to push in?
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Re: ST165 front brake calipers sticking?

Postby machomateo » Sat May 30, 2015 10:38 pm

BlackDragon wrote:If you open the bleeder, does the piston go right in or is it still hard to push in?


That's a good question, I'll have to check that when I'm not at work. That would mean the line is blocked? If that was the case, how would it be possible to bleed the system? It bled like any other braking system, fluid was definitely fresh from the reservoir because I had to keep adding and you could tell the difference between the new and old fluid.
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Re: ST165 front brake calipers sticking?

Postby BlackDragon » Sat May 30, 2015 11:32 pm

Yeah but the problem isn't the fluid flowing into the caliper, it's a problem with it flowing back and allowing the caliper to release. You have to keep eliminating possible culprits until you get to the problem.
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Re: ST165 front brake calipers sticking?

Postby machomateo » Mon Jun 01, 2015 2:58 am

machomateo wrote:
BlackDragon wrote:If you open the bleeder, does the piston go right in or is it still hard to push in?


So with the bleeder opened the piston are easier to push in. Decided to disassemble, clean again, lube again and reassemble. Still made no difference. I'm about to just buy a rebuilt caliper even though I just rebuilt this one. Very frustrating.
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Re: ST165 front brake calipers sticking?

Postby Toyota1968 » Mon Jun 01, 2015 3:35 pm

That says your problem is probably not the caliper...... Have you used a new master cylinder?

Did you have problem before installing braided hose?

Are both calipers locking or only one......

If both calipers ok to release when bleed open the problem possibly in master cylinder...... Make sure there is the slightest bit of slack between the master cylinder and pedal..... To ensure the master cylinder is releasing fully.......

For trial you could loosen mc from servo when brakes jammed to see if pressure releases......
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Re: ST165 front brake calipers sticking?

Postby machomateo » Mon Jun 01, 2015 5:48 pm

Toyota1968 wrote:That says your problem is probably not the caliper...... Have you used a new master cylinder?

Did you have problem before installing braided hose?

Are both calipers locking or only one......

If both calipers ok to release when bleed open the problem possibly in master cylinder...... Make sure there is the slightest bit of slack between the master cylinder and pedal..... To ensure the master cylinder is releasing fully.......

For trial you could loosen mc from servo when brakes jammed to see if pressure releases......


Master cylinder and vacuum booster both new (or rather bought re-manufactured) The braided lines have been on the car since I got it. It was both calipers but, I rebuilt both of them and now it only seems to be just one that is locking.

I will check the slack between the MC and the pedal, but from what I remember it was fine, I will double check though.
What do you mean loosen the MC from the servo? What servo?
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Re: ST165 front brake calipers sticking?

Postby Toyota1968 » Mon Jun 01, 2015 7:37 pm

Servo = vac booster , mc = master cylinder
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Re: ST165 front brake calipers sticking?

Postby 88gt4DE » Sun Jun 07, 2015 2:55 pm

MY bet is on the master cylinder / rod / booster slack too ...
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