93+ brake upgrade, caliper questions

[ansys]

alright everyone, looking for some opinions. I'm in the process of slowly upgrading to the 93+ brakes with these parts that have probably been sitting around a while. I've got a few options...

1- just install them as-is and hope for the best... (what should/could I be doing to inspect the calipers before install? I don't have compressed air at home to push the pistons out, but could try and push them in?)

2- professional caliper rebuild? any decent shops in Auckland that anyone recommends? Any estimates as to how much would this cost for all 4 corners if I just brought the calipers in? or maybe just the rears?

3- try and rebuild them myself... though I'm probably lacking some of the tools required, and haven't done it before. Suggestions on best/cheapest place for the rebuild kits? What's the price estimate on these?

4- I haven't decided if I'll bother painting them, but recommendations on caliper paint?

5- ???

I've already found these guides that look like they'll be handy, though the rear calipers looks like a pain?
front: https://mr2.org.nz/forum/viewtopic.php?t=10991
rear: https://mr2.org.nz/forum/viewtopic.php?t=8790

Phil (GDII), if you read this, I'm curious how much those Toyota rebuild kits were, and how well that red paint held up, as you wrote you had some concerns with it.
viewtopic.php?f=27&t=9444&hilit=Brakes& ... 40#p116455
https://mr2.org.nz/forum/viewtopic.php?t=9444&start=570

[GDII]

1. Rebuild. The kit is cheap. You could take them to a shop to get them removed if you want to rebuild. I don't think you need special tools except for maybe an O ring in the rear calipers. I didn't do that nor the seal on the handbrake crank pivot because lack of SSTs. No leaks so far.

2. If you want to get someone to do it that will give you piece of mind they are right. Supply them with the Toyota rebuild kits.

3. If you follow the BGB and guides you should be OK. But remember these are big safety items so if you are concerned about it don't do it yourself. I'm all for encouraging DIY but just keep that in the back if your mind.

4. I've seen a guy use 2K spray cans for colour and clear. Then he proceeded to completely cook the brakes as a test and the paint was still fine.

Rebuild kits at the time were $110 for both front and rear all up from Toyota but they will have gone up since then.

Front kit for 36T25 and 36T30 is 04479-17020. Note the piston size is the same for both hence 36 in the code.
Rear kit is for 22V only 04479-17040.
Obviously these are shown in my write up in the links you provided.

As for the paint I used. I got it for $20. Duplicolor brush on caliper paint. It is very hard paint so any taps on it from anything hard make it chip. I did not prime them, probably should have but other than the chipping it's not too bad for $20. If I was doing it again it would be powder coat. I have since coated them in 3 layers of CarPro DLUX ceramic coating and it's so good for cleaning them.

[Benckj]

Just adding to Phils comments;

2/ Must rebuild calipers with new seals and sliders. Shouldn't cost much to have mechanic do as its an easy job if removed. Can be tricky even if you have special tool.

4/ Defintely paint while you have the chance even if its black. Makes cleaning much easier and looks great through open alloy wheels. You will kick yourself later if you see rusty calipers. I used a small tin of high temp barbeque paint.

5/ Good time to install braided lines to calipers. Consider upgrading MC to gen 3 (think its 15/16th) and rebuilding as well. When installing new fluid go to DOT 4 or better yet 5.1 for higher temp rating. Consider what pads you want to run for street/track use. Get rotors refinished if they have groves or are warped. Best to check first.

[GDII]

Just adding to Phils comments;

2/ Must rebuild calipers with new seals and sliders. Shouldn't cost much to have mechanic do as its an easy job if removed. Can be tricky even if you have special tool.

4/ Defintely paint while you have the chance even if its black. Makes cleaning much easier and looks great through open alloy wheels. You will kick yourself later if you see rusty calipers. I used a small tin of high temp barbeque paint.

5/ Good time to install braided lines to calipers. Consider upgrading MC to gen 3 (think its 15/16th) and rebuilding as well. When installing new fluid go to DOT 4 or better yet 5.1 for higher temp rating. Consider what pads you want to run for street/track use. Get rotors refinished if they have groves or are warped. Best to check first.

DOT4 may have a lower boiling point but it absorbs water slower than 5.1. I use TRD fluid that is DOT4 but a boiling point of 600°F or 315°C. It's also quite cheap if you buy from North Shore Toyota.

Quite right with points 2 and 4. Yes, a high temp paint for say, engine blocks will work too. Depends on the colour you are after, some coatings will only come in certain colours.

Also it's 92+ JDM for the calipers AND the master. REV1 89-91 is 7/8 and the REV2-5 is 15/16 like you say Jim. They did change the booster too and made a few revisions to the bias valve between 1990 and 94. This bigger master makes pedal travel less than REV1 but more force on the pedal although probably changed that feel wit the booster but the piston size is the same even though the brakes are bigger. Toyota just adjusted rotor size and adjusted the brakes and caliper castings to suit.
I assume you've read this Paul?
viewtopic.php?f=13&t=15191

[ansys]

Thanks for the tips you two. Yes, I have seen the really handy brake parts reference that you linked to. It's a nice resource to have!

I bought the brake bits off a parts car pretty much, which came with pretty much all four hubs and bits attached, braided lines, and a booster/MC.

Unfortunately, the front disc dust shields do not match (the left one is the updated slotted version, and the other is the older, original version just bent back). So, I'll most likely be bending the originals that are on all 4 corners of my car already. How much clearance did you give the rotors when you bent yours back Phil?
I'm also curious how much extra cooling capacity the slotted dust sheilds in the front gave vs. the originals, as my main reason for upgrading is fade resistance as opposed to any increase in stopping power. (it seems like the design for the rears is pretty much the same). If it comes down to it though, I've also got a set of the Porsche 997 GT3 front brake ducts that I saw a youtube video of someone installing on an MR2 with supposed success. They only cost about $20 from the Porsche dealer, so I figured why not.

As for the MC, the 'kit' that I bought came from someone that was using a 1" MC from a Hilux or something, so unfortunately it is not the 15/16" of the OEM. I'm going to guess that the 1" will feel better than the original 7/8" though, so will try that out and see how it goes. If anyone has any experience using a 1" MC with these brakes, I'd be interested to hear your thoughts!

[GDII]

I bent mine back to clear. 1mm is clear

As for heat, the shields will hold some vs having the 92+ ones but having none at all will almost be better minus the fact the fronts have a duct to direct air to the rotor centre.

In my experience the 1" was great on track but terrible for the road. I feel my pads were too track orientated for road use so I went back to the 15/16 and it's much nicer for the street. Too much foot pressure is required for the 1".

As you've probably read, master cylinder vs slave cylinder sizes change 2 things. Slave being the calipers. The 7/8 on the REV1 requires more travel but less foot pressure to create the same pressure on the pads vs the 15/16 on the REV2-5. This master requires more foot pressure but less pedal travel for the same pressure on the pads. The 1" I got from a Previa is bigger again so shifts the foot pressure higher again and pedal travel less.

If you have both 15/16 and 1" and feel like bleeding the system a few times and doing testing for yourself then go for it. You'll know what you like but from what I found I liked the 1" for the track although never used the 15/16 on track but I assume it wouldn't be that bad bit a little more travel and possibly harder to control once things got hot? Again, test it, see what you like and go from there. Its a cheap part to swap and isn't too hard.

[ansys]

Unfortunately I have both the 7/8" of the Rev.1 and the 1" MC. I do not have the 15/16" from the Rev.2. I heard of people continuing to use the 7/8" MC with the 92+ brakes without a problem. How do you feel about that setup? From the sounds of it, I'm not sure I'd like the hard pedal with minimal travel of the 1" setup

[GDII]

Unfortunately I have both the 7/8" of the Rev.1 and the 1" MC. I do not have the 15/16" from the Rev.2. I heard of people continuing to use the 7/8" MC with the 92+ brakes without a problem. How do you feel about that setup? From the sounds of it, I'm not sure I'd like the hard pedal with minimal travel of the 1" setup

Like I mentioned earlier, the caliper piston size didn't change so the master is still 'matched' to the REV1 brakes. Toyota just made the upgrade to 15/16 and also the booster changed so the feel would have been a similar pedal pressure. No problem running the 7/8 on the 92+ brakes.

Yeah, the 1" is quite stiff with the REV1 booster. I never got the updated booster. For street, too stiff, for track, I liked it.

[ansys]

The further I dig into this, the more questions I end up with!

So, these are the parts I have at my disposal...

Rev.1 brakes currenly installed on the car:
- 7/8" MC
- the w18 booster
- a proportioning valve that has '56' stamped on the casting near the "F" port

Parts that came from a donor car:
- 92+ Calipers
- a 1" MC from who knows what.
- the w53 booster.... (which I think might be the ABS version????), unfortunately, I learned today that I do not have the check valve for this booster!
- a proportioning valve that has '53' stamped on the casting near the "F" port. Looks identical to the one on the car already.


You mention the 1" is stiff with the Rev.1 booster, what about with the w53 booster?

Aside from the check valve, what's the difference between the w18 and w53 boosters? (or even between the non-ABS w51 and ABS w53)

Is there any difference in the proportioning valves?

If I just change the calipers/rotors while leaving the Rev.1 Booster and MC, how will pedal feel change? Does anyone have any experience with this setup? I'm not sure I want to bother with trying to source and reroute the brake booster check valve for the w53 booster

[GDII]

I don't know the answer to those questions.

If you swap the calipers over and nothing else the pedal feel should be very similar based on the fact the calipers piston size hasn't changed.

[ansys]

yeah, you're right. For some reason I had it in my head that the Rev.1 fronts were single piston...It's been a while since I changed out the front pads, and I've probably been thinking about this brake upgrade too much and for too long haha.

I went back through your build thread, and interesting that your prop valves had 58 and 54 cast on them for the Gen 1/ Gen 3, whereas mine are marked as 56 and 53 respectively. They look the same as the ones in your photos.

[GDII]

The 5SFE powered ones got single pot fronts.

I don't what the numbers mean or the exact difference between them but if you look at part number changes you might find that there are several for REV1 and REV3.

You are probably overthinking it a little more than normal but you've learnt a fair amount because you are curious.

Get it done and go enjoy some track time!