6G Celicas Forums

I am about to change the brakes on my '94 GT, and was wondering about the ABS system.

Now, a lot of ABS systems are of the closed loop variety, which means that in order to completely bleed the system, you have to do one of two things: either take it to a dealer to get them to hook up a snorkelator which electronically activates the ABS, allowing access to the normally closed ABS loop (or perhaps have one of these snorkelators yourself and know how to use it).. which is the preferred route; or you can bleed the brake lines, take the car out on the road, and slam on the brakes and activate the system (which in theory will flush new fluid into the loop), then bleed the brakes again. The latter doesn't really strike me as a very good way of doing this, as you are never sure of the fact that you got all the old fluid out.

Typically, on these closed loop ABS systems, the bleed steps are different than what you would normally expect from your plain jane brakes (i.e. you don't start at the wheel farthest from the master cylinder and work towards the closest). Looking at the Factory service manual, though, it says that the bleed steps for ABS are the same as non-ABS. So my question is whether or not the ABS system on the '94 GT is a closed loop variety, or if a regular bleed is going to accomplish a complete flush of the system. Logic kind of points to the fact that it will, but I was wondering if any of you have some input on this.

I am replacing the bleeder valves with SpeedBleeders, and going to Hawk HP Plus pads on the front. Stock Toyota pads on the rears. Fluid is SuperBlue. For those of you that bleed your brakes yourself, and haven't tried SpeedBleeders and/or SuperBlue fluid, I can't recommend the stuff enough. The bleeders let you do it yourself, and the fluid is electric blue, so you KNOW when the lines is completely flushed.

~Mark

How muck are those speed bleeders? I'm gonna put valvoline synthetic brake fluid on mine. Is that blue stuff synthetic? I don't think that it matters if your car has abs or not. Pumping the pedal will still flush out the fluid. Not sure though.

They cost me about $35. You can order them Here

They don't have the Celica listed on their web page, but they do carry them, you just have to call them and ask.

ATE Super Blue Brake Fluid is not synthetic. It is DOT4 fluid. One thing to point out to you about synthetic fluid is that it is NOT hygroscopic. Moisture can form in your brake lines under normal use, whether it be via condensation, humidity, or even washing the car. If you are using synthetic fluid, this moisture cannot be absorbed into the fluid (which is one of the reasons you should bleed your brakes and changes fluid every year or so). The result is that you have little droplets of water that form in the fluid, and if they are near the caliper, which reaches operating temperatures above 200F. If this occurs, the droplets can boil, resulting in vapor lock. Even if the little drops don't boil, just think, now you have water droplets wandering around in your lines, rusting and corroding your parts from the inside. I am not telling you not to go synthetic, but I just wanted you to be aware of the consequences.

If you are curious, you can check out ATE SuperBlue Here

It is expensive, but well worth it in my opinion.

Hmmm, you haven't convinced me

DO NOT USE SUNTHETIC FLUID!!!!! Its totally worthelss and I don't know why it is even sold. Probably just because people just assume that its better because its 'synthetic' and buy it, I can see me doing that. But its not better!

I don't have a lot of experience with ABS systems as I've never owned a car with one and I've only worked on them a few times. If you have a toyota shop manual its definitely correct. I'd just follow the instructions in that case.

I had to replace the master cylinder on my 99 solara with abs and it just bled like a conventional system. I think the system was very similar to the one used on the celicas. (2 lines in, 4 lines out) not positive though because my celica doesn't have the abs. But like spedtoe said, I would just go by the repair manual. Good luck.

But synthetic has a higher boiling point. Why is it useless? Brake lines get hot and the fluid has a certain temperature range. Once it exceeds that it becomes less consistent.

Synthetic brake fluid is not completely useless, but for all intensive purposes, it is not advantageous to use it. The reason is, as mentioned above, that is does not absorb water. One of the functions of brake fluid is to absorb and disperse the water in your brake lines. This is the main reason people should bleed their brakes every year or so, to flush out the old fluid that has absorbed water (which is a good thing, since it is not corroding your lines). As the fluid absorbs water, its boiling point goes down, again, another reason to bleed your brakes. Under normal conditions, your brakes will never heat up to a temperature such that this will even matter. An emergency stop from 100+ mph won't do it. A lot of autocross runs back to back *might cause you some grief, but probably only on neglected systems in the first place. Track days, on the other hand, willstress you brake system, and likely cause boiling unless you are on top of things.

The people who get benefit from synthetic fluid are race cars or cars that do extensive lapping on road courses. I guarantee you that most, if not all of these people bleed their brakes after every single session on track. Humbug! you say?! I think not. Ever use SpeedBleeders? They are flat awesome! I can bleed my entire brake system in 20 minutes, by myself. Water hasn't a prayer of forming in the lines, and therefore the risk of corrosion is nominal. Like you mentioned, one the fluid exceeds the biolign point, in becomes less consistent. Another reason the track guys bleed so often. I know I would.

I am pretty sure this was what he was referring to when he said it was completely useless. I would never use it, and I autocross extensively. I simply don't reach those temperatures, even under those conditions. I think the best bet is a very good DOT4 fluid. It has a high boiling point andabsorbs moisture. I bleed my brakes about twice a year, but that is probably overdoing it.

I am not telling you not to use synthetic fluid. I am telling you that you should be aware of the consequences of doing so. I don't think you need it, I know I don't, but ultimately you have to make up your own mind about this. Bear in mind that one drop of water near your caliper will boil at 212 degrees fahrenheit. I bet your synthetic fuild won't boil, but the water it won't absorb will...

Ok, its not completely useless, but its definitely not any good for anything I'd ever do. If the system is properly cared for then its not an issue.

Not really. You'd be hard pressed to find a racer that uses synthetic fluid. You'd also be hard pressed to find a 'racing' brake fluid that is synthetic. My full time job is mainitaining race cars. I have 5 cars to worry about and we've never ever used synthetic in any of the cars. We use AP Racing calipers on the World Challenge cars and they have a fluid designed specifically for those calipers. I don't know how it differs from other fluids, but its a non-synthetic.

We do bleed the brakes after each and every session. Once you get good at it it doesn't take any time at all. We can do it quicker without speed bleeders, but only because there are always multiple people around to do it. I have the speed bleeders on my celica and I love them.

teh

Admittedly I was extrapolating on that one. Racers who bleed all the time and could benefit from the high boiling point are the only group I could see really taking advantage of any bonuses that synthetic fluid has to offer.

I am curious as to why you don't use synthetic fluid. Is it something to do with the special calipers or something?

This post has been edited by ConeTrouble: Dec 18, 2003 - 2:43 PM

haha, I wasn't trying to OWN Joo! There are a number of reasons we don't use it. First of all, the AP fluid is designed to be compatable with the seals used in their calipers. Other stuff would probably work, but in racing probably isn't ever good enough. Second, as you mentioned the synthetic fluid doesn't absorb water. Whenever you take the cap off the system the ambient air fills any space in the resivor not occupied by fluid. In a racing system the fluid gets very hot, well over 100deg while on track. As a result the fluid expands. We run our fluid levels lower than you would in a street car because of this. Thus, more air space and more moisture. Its better to have the fluid absorb it than have it alone in liquid form (later in a gas form). Anyway, we don't really need the additional boiling point afforded by the synthetic fluid. If your fluid is getting hot enough to boil then your disks are alredy over temperature and you need to revise your brake ducting. We've got this trick thermal paint we put on the rotors, so we always know how hot they're getting. Its really interesting how the ducting setups vary from track to track. Some tracks don't hardly need any. Some tracks need a lot of air on the rotor, others need more on the caliper.

Lol, welcome to the board. You sound like an excellent resource of knowledge.

bleeding ABS brakes is the same as bleeding none ABS.


this is from the toyota service manual :

BLEEDING BRAKE SYSTEM

Brake bleeding procedure is same procedure used to bleed non-
ABS systems. If master cylinder was rebuilt or reservoir ran empty,
bleed master cylinder first. Bleed remaining wheels, starting with
brake having longest hydraulic line, working to brake with shortest
hydraulic line.

lagos: Yep, that is the section of the manual I was referring to. Thanks for posting that section.


I had hoped to do my brakes this past weekend...

I pulled the car into the garage, jacked the car up, put it on stands, pulled the wheels, calipers, pad cage, took out the old pads (noting the orientation and location of those spring clips!!), cleaned everything, went to put the new pads on..... They don't fit!

*stumbles around the garage trying to figure out what to do*
*scratches my head* (My girlfriend asks me later why there is black stuff in my hair...)
*trys to concoct some way to use aluminum foil to hold the small pads in place*
*calls Toyota dealership.... closed*
*curls up in the fetal position one corner of the garage, sucking on my thumb*

Guess they will have to wait until after Christmas. I did notice my rotors were scored in a few places. Lots of pad left, so I am guessing that the last time they were replaced that the pads had worn down all the way to the backing plate, and whoever did the work did not turn the rotors... Any tip to pulling the rotors off? Is it a couple bolts, or is it pressed on? I will bring out the BFH if I have to. Something just seem inherantly wrong with using one of those on a car, though. Thanks for all the input, guys, and thanks for the welcome, Andason.

did you use a break pad install tool.. to push the piston back?

and as for the rotors you have to take the brake caliper off and the rotor just falls off with know problem.

I don't think I have ever seen a BrakePad Install tool. I always just used a C-clamp to push the piston back in.

That wasn't the problem, though. It was the fact that the pads were too small. The backing plate did not match the ones I removed. I was joking about trying to fix it with aluminum foil

Thanks for the rotor tidbit. Nice to know.