Do I need to do anything special w/regard to the ABS
when changing my brake fluid? Car is 1993 w/ABS.

Going to change fluid for first time this weekend,
going to try the old fashion way, just using pedal.
BTW, how much do you guys that do this usually use up?
Just bought a 1 liter container of the good stuff--ATE Blue.

Thanks.

 

I was never for certain that I did mine completely the right way, but it seemed to work out fine. I was replacing the lines to s/s braided and put new front calipers on, so I had some empty space in the system. I used a mity-vac though. Seemed to be a much easier way to go. I emptied what was visible in the master cylinder and filled with new fluid. There is a bleeder on the ABS. I think you need to do that one first, and it has something to do with bleeding the rubber hose that connects to the side of the m/c. Then do each caliper. I used the mity-vac to pull new fluid through each line, which should also end up purging the ABS unit also. I would top off the m/c each time I used the mity-vac. I used most all of the bottle to make sure I had all new stuff in.

 

"Bleed your brakes like anyother system. The ABS does not matter." - Gordon Killebrew.

Enjoy!

 

There is a bleeder on the ABS?

How would you activate the ABS pumps to bleed it? I guess if it was before the ABS unit I could see bleeding it in a normal fashion.

I know some of the later models require a scan tool to activate the ABS pump and bleed that way.

On my 93 I replaced the master cylinder spring which required complete bleeding of everything, including the master cylinder. To take into account the ABS pumps, I did this: I bleed the system at each caliper starting with the furthest away (passenger rear) caliper first like I would any other car.

I took the car out when it was wet and attempted to lock the brakes. I heard the ABS pulsing. I got the ABS to pulse a few times. Then I bleed the brakes a few months later and assumed I got whatever air that might ahve worked its way into the ABS unit out.

Seems to work fine. Although the stock 12 inchers are crappy brakes to begin with.

Good luck.

 

your making this too complex.

Just bleed as normal. The ABS pump gets fluid inline to the rest of the system, the high pressure side has its own issues, but the low pressure side is gonna be bled when you do the rest of the system.

 

I've never used a mity vac for bleeding. Is all you do is attach it to each bleeder valve, open it and pump away? Do you have to push the brake pedal in at all? Doesn't the bleeder valve leak around the outer edges of the threads when you provide a vacuum?

 

If the ABS portion of the system has to be bled, the GM tech use a Tech-1 with the brake system module. They can then energize the ABS pump and flush the fluid from the ABS sie of the brake system. Unless you have a problem with very dark, dirty fluid or air in the ABS side, the ABS will gradually bleed itself as the system does its self-test each time the car is started and it hits 3-4 MPH.

I don't think there is a bleed valve on the ABS system but there is a plug that can be removed to bleed the ABS module. It can get pretty messy in the compartment if you do bleed the module.

 

if you are using a mityvac you need to have a bleeder bottle to capture the fluid. you dont want to suck it into the pump. If you choose to use the pedal pump method I would be careful not to push the pedal to the floor. By doing this the piston in the master cylinder will be traveling past its normal position and could harm it. You could use a block of wood as a stop so the pedal won't travel too far.

 

Ok, so consensus is that I don't have to do anything to this, maybe I'll see after I drive it for a while if there is new air from the ABS which needs bled.

Thanks for the tips, especially the block of wood--wouldn't have thought of that!!

 

Never used the mityvac successfully. I found too many air bubbles in the line and could not account for them. Seems like the air went past the bleeder screws to give the false impression of air in the lines.

The way I did it is to empty the reservoir and then remove the reservior and clean it throughly with brake cleaner. I also sucked off the master cylinder so there is nothing in the stacks where the reservior sticks into. Then I replace the reservior and fill it up.

Here is where there are 2 options. You can attach a pressure bleeder which forces fluid into the reservoir and then when you open the appropriate screw, it bleeds out till it is clear or you can do the old method of "Open, Down, Close, Up.

I like to stick a clear hose at the nipple so that once the fluid gets clear, I stop the process and go to the next one. The mityvac has too many bubbles for my liking especially when you are done. I never know when it is all bled off.

It is harder to see clear fluid for me because I flush annually.

Just my $0.02

 

Hehehhe....ME too!!! I bought the dadnabit $300 super duper Phoenix injection system. Useless!! I have tried it on bikes, cars, clutches, brakes.... you name it. I don't even open the case anymore.

Ever watch that British guy, Mark (somethin' or the other) on do it yourself stuff like a "bike is reborn" or a "car is reborn". Well, one night he was going to use his new fangled super duper brake bleeding system (forget the brand) to bleed a bike hydraulic line. He tried, and tried, and tried....it was funny. He then looked into the camera and announced, "the reason you folks out there can't find any brake fluid in the entire village is because we have bought it all trying to use this system"....I had to call several friends on that one...........

 

I re-checked my Helms to make sure I wasn't crazy. There is in fact a bleeder on the ABS module, on the right side. It looks just like a caliper bleed screw. The rubber hose that connects to the side of the master cylinder reservoir is a prime pipe for the module. The bleed screw on the ABS is to bleed this line. Now the only reason one would have to do this is if your fluid level got extremely low, or if you disconnect the m/c. For everyday bleeding, it isn't necessary. But if you are wanting to purge out all old fluid and replace with new, this line should be done also. My manual says it must be done before any of the calipers. Yes, it will be messy - unless you are using the mityvac. It sucks it right up into the canister.

I did not have any problems with the mityvac. I thought it was slick. Basically it is a pump that draws from the inlet hose and puts it in the reservoir. My technique was to attach the inlet hose to the bleeder nipple and pump it up to maximum vacuum with the bleeder closed. Then I just barely cracked open the bleeder until I saw it start to draw fluid in the hose. When the reservoir was full, I closed the bleeder. Yes, if you open the bleeder too much, the mityvac will pull air past the threads and into your inlet hose. You are not introducing air into the brake line, but you get the impression there is air in the system because you see it in the hose. The key is to not open the bleeder screw so much.

 

I never bleed the ABS pump. It cycles on every start cycle and moves fresh fluid through it. If your Vette has real old brake fluid, flush it once a month for 2-3 months, the start cycles will move new fluid in and the old stuff into the regular brake system. After all the old junk is out of the system, flush it once a year to keep the ABS pump from dying.

Eric