puzzling brake issue here

[gsxr141]

for the past month or so, i would get an intermittent "hard" brake pedal. i attributed this to the very low idle that my car sometimes has.
fast forward to today.... i went on a fairly long drive to pick up some car parts and my car had a slight pull to the right and a front end shimmy around 60. i also had a brake smell coming from the front.
eventually the shake and pull went away, until i was close to home. the pedal got hard and the car was practically coming to a stop when i let off the gas. i pulled in the driveway and let off the brakes to roll down the hill and NOTHING. the brakes were locked up.
within 5 minutes i jacked up the car, and found both front wheels free. wtf? i did also find a loose inner tie rod end.
before i throw calipers and hoses at this thing, does anyone have an idea what could be the problem?

 

[hvyman]

Slides could be sticking or the piston.

 

[Maple191]

Hard brake peddle could be a failling brake booster. As for the brakes take them off and inspect the calipers, get a pair of channle lock pliers and try to push the piston back. MAKE SHURE you do it with caliper is in a natural postion. (Not being inverted while sitting on the slider) And check you slider, try to move it and put a dab of sil-glide grease on them, as well as the boots. If the slider is seized try to take it out carefully, and put it on a buffer wheel if you have or know someone who has one, if not just use a wire brush. And check to see if you pads are seized in the saddles, whether they are or not its always a good time to put copper slip on them.

 

[gsxr141]

sorry, i should clarify. i know what to look for as far as checking the brakes, i just wanted to know if there was some "supra specific" reason that both sides would do it at the same time.

 

[Maple191]

Are they original calipers? They probally need a rebuild

 

[gsxr141]

so, here's a fun update. tuesday at work i tried bleeding the system with the pressure bleeder at work..... i got a little fluid out of the rears, and good flow out of the right front, but NOTHING out of the left front. when you step on the pedal all the wheels stop, but i still have a weird feeling pedal.
add to that, when i pulled the car out of the shop my braided power steering pressure line blew. i went ahead and ordered a new one from driftmotion as well as the braided brake lines.
wish me luck.... and feel free to chime in with any suggestions.

 

[Compton74]

your car abs?

 

[gsxr141]

yes. any ideas?

 

[T701jz]

If these were all 20 year old parts I'll replace every single parts that has anything to do with the brake system...(calipers, pads, lines, master cylinder, booster, rotors..etc) This is how much I value my passengers life.

 

[gsxr141]

believe me, i have no problem replacing everything that needs to go. i'm just puzzled at what the car is doing. i just find it odd that BOTH front wheels would "lock up", and then act fine. i've never seen 2 calipers seize at the same time, let alone free up that quickly.

 

[radiod]

My guess would be deteriorating soft lines and junk getting stuck in there. I've seen the same sort of thing just not to the same degree of locking the brake up completely, but a partial lock up.

 

[3p141592654]

I would suspect the ABS modulator. You see any activity with the ABS light? You can check for ABS codes, but I doubt you will find any if the abs light is not on.

 

[gsxr141]

The abs light has been on since i've owned it. I just assumed it was because of the auto to manual swap.

 

[3p141592654]

Does your manual gearbox have the tailshaft speed sensor? In any case, even with the light on, the modulator should not behave badly and is designed to fail safe. Sounds to me like the internal valving may be gummed up. See if you can get any codes first though.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=BR&P=51

 

[gsxr141]

i'm not sure. the antilock light comes on after driving a short distance. it is off again when i get back into the car. i drove it home today and it started pulling to the right on the brakes. i can smell "brakes" on the right side also. i'm going to start with the right caliper.

 

[mshaw067]

id replace the brake lines going to the calipers they could be collapsed if that is the case they wont always show signs of needing replaced only when they want to lol and its a fairly cheap fix. not to mention its a great reason to swap out for upgraded parts
let me know if this helps

 

[jonahs_supra]

if your brake pedal is hard at random times then i would suspect the abs modulator is bad
try unplugging the electrical connectors
then see if the issue is happening

wouldnt be a bad idea to replace both front caliper and hoses
im sure the calipers are begining to seize up at times

do you have access to a pressure bleeder or able to gravity bleed brakes for a extended period of time?
im puzzled your not getting a whole of fluid from the rears
try driving car on gravel and slam on brakes to activate the abs pump(if it still works and im not to sure if theres a way to active pump to bleed brakes)
then try to bleed the brakes again

 

[gsxr141]

i ordered braided lines from driftmotion the other day. unfortunately they won't be here till next week. i just ordered front calipers from rockauto today. i'm probably going to pick up a brake booster from a member here to throw on as well.
i also ordered a front wheel bearing. i think the one on the right is bad, and may be causing the other issues.
thanks for the help guys.

 

[destrux]

I would start with a brake booster. From everything you described, it seems like the most likely culprit.

Just be sure you install it right and (most importantly) adjust the pedal free-play correctly as per the factory manual.

 

[gsxr141]

hello all. i'm still having some brake issues with my 90 supra.
long story short....... i was getting an intermittent hard pedal after driving a while, but it wasn't a big deal. for the last month or so the pedal would get hard AND the front wheels became hard to turn. if i let the car sit overnight it was all good in the morning. i previously installed a new master cylinder, so i counted that out as a problem. also, the problem is only with the front wheels.
saturday i installed new front calipers and new driftmotion front hoses, hoping this would fix things. it did not.
has anyone had this problem? or does anyone have any ideas as to what could be the problem?
thanks.............. kevin