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stop pulling me over pigs
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Discussion Starter · #1 · (Edited)
Last weekend my break pedal went to the floor. Three weeks prior, I has just put on new (thicker) front rotors - my other rotors were worn down past the limits. I didn't think I needed to bleed the system, since I was just replacing the rotors. So, I bled the system up top at the master cylinder, and a few air bubbles came out. I also bled the two back wheels to be safe. After that, the brakes had better pressure, and the pedal didn't go down to the floor.

A week later, the brakes are still working, but the pedal will go to the floor if you keep pushing it. So now, I need to price a good oem master cylinder. would it be smart to just get the rebuild kit, or are they cheap enough to just replace the whole thing?

I saw some on ebay for like 30 bucks, but they have weird looking reservoirs...I want to keep the car oem. Any suggestions?

Also - is this a big job? Before I bust out my tsrm and supra hanes manual - I'm assuming that you need to drain and take out the master cylinder up top, and then get the new one on, bleed the entire system at all four wheels, etc...am I right? Is this a btich of a job that will take me all of Saturday?
 

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Sounds like you may need a lil extra help.... if you've not done this before, you should get someone that knows, to hang out for a bit...

You can get a rebuilt one from almost any parts store. MAKE sure to order the right one. Autozone kept trying to insist that some funky looking one would fit and was the right part number, but all they did was waste my time. You're looking at about $50 w/lifetime warranty from most places.

Make sure and bench bleed it according to the directions that come with it. Basically removing the air bubbles in the master cylinder before installing.

Get a 10MM semi-boxed wrench (I forget what they are called), but they are the ones that have a small opening to allow the wrench to fit over a small tube/pipe. Flare wrench? Also get some extra, decent fuild.

Should only take you about 20 minutes to change the master cylinder (yes, you will need to re-use the reservoir... don't strip that stupid screw that holds it on). Then, since it sounds like you already got air in your lines, you will probably need to bleed the heck out of the lines at the calipers.

All-in-all... maybe an hour...2 if you're really anal.
 

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Oh... BTW: Even when you get a rebuilt MC, it could still be defective. A few years back I replaced the one on my 87T and the wheels felt like they were dragging. As if there was constant brake pressure on 'em.

Anyways, took a bit of convincing, but they gave me a replacement 2 days later. Which should not have even been an issue since it was also a lifetime replacement deal. The parts manager was just being difficult.

Anyways, I priced what the rebuild kit goes for and what the rebuilt unit goes for and they were about equal. You have more warranty/gaurantee with a rebuilt one... none with a kit.
 

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stop pulling me over pigs
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Discussion Starter · #4 ·
good advice guys...yeah I have the right wrenches already. I'm going to liquid wrench / lubricate all of the bolts a day before, let them soak good so I don't have any problems getting them off. ugh I'm so sick of working on old cars, but hey this is what you gotta put up with when you love mk3 supras, and want to save money as compared to buying a newer car :)

I bet getting a master cylinder through toyota would be a rip off.
 

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Get a new one from Champion Toyota. The one I got from them was made of aluminum, my original was very heavy cast iron. The replacement has has lasted years.
 

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tomhw said:
Get a new one from Champion Toyota. The one I got from them was made of aluminum, my original was very heavy cast iron. The replacement has has lasted years.
Agreed. Rebuilts are a real crap shoot on these cars. I had 3 of them before I went and bought a new one. The inside gets ridged and just tears up the new pistons/seals. It gets to be a pain swapping these out and bleeding them over and over. Put the new one in and no problems since.

Marty
 

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Does the pedal slowly fall to the floor with your foot on the brake? Internal leak past the piston's seals in the m/c. If so, try this BEFORE replacing the m/c. Drain all the old brake fluid from the reservoir and refill with Genuine Toyota or Honda DOT 3 brake fluid. < WHY Toyota or Honda? It has better seal swelling properties than Prestone and other auto store brands ( it's a different formulation, totally clear and smells different)and it will reactivate the piston seals better than Prestone or some other brand. Try it! It worked for me on my friends '91 Integra that had the same problem after new Prestone brake fluid was added less than a week before. I drained it, filled up with OEM Acura/Honda, bleed the system and it's been fine for almost a year now. Original m/c with over 200k miles.
So all I stock in my garage is Toyota & Honda brake fluids for the 4 Acura/ Hondas and 1 Toyota owed in my family.
Mike
 

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stop pulling me over pigs
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Discussion Starter · #8 ·
Thanks for all of your feedback, guys.

I ended up buying an OEM rebuilt MC for around $55 with tax. Yesterday my father and I replaced the master cylinder, and bench bled it - put it back on, only to realize that we had remounted the reservoir backwards...so UGH we had to take it back off, unhook the two front lines, and bring it back in the basement. We didn't re-bench bleed it, since all we were doing was changing the reservoir. I would have, but the little plastic hose fittings used for bench bleeding had gotten stripped, and wouldn't screw back on - those things are so freakin cheap...frustrating to screw something plastic into a metal thread only to realize that it keeps cross-threading, and there are no more that come with the kit.

All back together, the brakes were still really spongy, almost going to the floor, but at least not fading like they were before...So with it all back together, we bled the master cylinder up top at the fittings (just fluid came out, no air bubbles) and then back right wheel for the heck of it, and my dad noticed that the caliper was MOVING about a QUArter Inch - whenever the brakes were applied. We whipped that wheel off, and found that the pads were only about 1/3 of the way gone, but the caliper was rusted on the little pin it rotates on - the part that allows you to move it in and out, after you swivel it up. We sprayed the upper pin with penetrant, but that thing was rusted on there good. We stopped the caliper movement by putting in brand new, thicker rear pads. The brakes feel as tight as they ever were on the car now. But as soon as they wear, maybe in a year or so - the problem is going to come back. They'll be just as spongy as soon as that seized caliper starts having more room with less pad wedged in between it.

Does anyone have any calipers laying around? I would need the entire assembly, not just the upper half, but the lower half that bolts onto the rotor as well. I am going to have to price those - unless I can work on it and keep on spraying penetrant in there. Has anyone else had any problem with these calipers getting rusted/stuck?
 

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TheSUPE87 said:
Thanks for all of your feedback, guys.

..........

All back together, the brakes were still really spongy, almost going to the floor, but at least not fading like they were before...So with it all back together, we bled the master cylinder up top at the fittings (just fluid came out, no air bubbles) and then back right wheel for the heck of it, and my dad noticed that the caliper was MOVING about a QUArter Inch - whenever the brakes were applied. We whipped that wheel off, and found that the pads were only about 1/3 of the way gone, but the caliper was rusted on the little pin it rotates on - the part that allows you to move it in and out, after you swivel it up. We sprayed the upper pin with penetrant, but that thing was rusted on there good. We stopped the caliper movement by putting in brand new, thicker rear pads. The brakes feel as tight as they ever were on the car now. But as soon as they wear, maybe in a year or so - the problem is going to come back. They'll be just as spongy as soon as that seized caliper starts having more room with less pad wedged in between it.

Does anyone have any calipers laying around? I would need the entire assembly, not just the upper half, but the lower half that bolts onto the rotor as well. I am going to have to price those - unless I can work on it and keep on spraying penetrant in there. Has anyone else had any problem with these calipers getting rusted/stuck?

^ Why change the caliper and torque plate? Just buy a new main pin, mounting bolt and main pin boot from Toyota and lube it up well. It's not that expensive. The main pin (the top one that the caliper pivots on) bolts to the mounting plate. Toyota calls this plate the "torque plate" Buy a new main pin as they corrode and hang up if the boot was cracked
You might as well replace the sliding bushing and its boot. < ( the one on the bottom).

http://www.cygnusx1.net/supra/library/EPC/MKIII_NATO/291420/4707_1.html
 

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That, and there are plenty of non-rusted pieces on many of the parts cars out there. Cheap and easily available.

Glad you were able to figure yours out... mine are still somewhat spongy and I'll be rebuilding calipers and all kinds of stuff (after the swap).
 

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stop pulling me over pigs
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Discussion Starter · #11 ·
thanks for the advice guys, I appreciate it

I've noticed that all the toyotas I've ever driving (camrys, corollas) they never seem to have a really firm pedal - maybe it's just the way they are. My dad's pontiac bonnevilles are hard as a rock, and all you have to do is just touch the pedal gently with your foot, and they start to stop the car. It's kind of nice. You do get used to the Toyota sponginess though, after driving with them so much. Do any of you guys notice this about toyota braking setups? Maybe some stainless steel braided brake line kits would improve it. I know there's someone that made a thread a while ago that sort of get rid of a lot of play in the MC by bending a custom bracket and bolting it to a strut tower bolt - and supposedly that helped it a little.
 

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I replaced the calipers/stainless lines, new pads, new master cylinder/rotors, the whole car feels like a new one when braking. Makes a huge difference.
 
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