tombrammer

Exactly how do you flush the brake system on a 93 vett? The FSM says to start at the wheel furthest from the reservoir but if you count the distance from the ABS near the rear axle it seems to be the front pass side wheel? Do you drain the reservoir first somehow? Any other pointers would be appreciated.
And how do you flush the clutch slave?
Thanks

mashinter

I suck the old fluid out of the reservoir with a turkey baster, fill with new, and gravity bleed the wheels until new fluid appears.

HlhnEast

I need to do this too and I will use the gravity method on the brakes. The clutch will require a little more effort. A recent post on this indicates the need to "level" the clutch master cyl by jacking the car appropriately to remove trapped air. The poster used a vacuum pump and did it in 5 minutes.

jaa1992

For my brake fluid changes I bought a vaccum bleeder that attaches to my air compressor.
Harbor freight has a hand vaccum pump on sale for about $15
Motive makes a power bleeder that uses pressure at the master cylinder

Get a quart of good dot3 or dot3/4 fluid - I use valvoline synpower
Remove as much fluid as possible from the master cylinder
fill to the neck of the master (this is way over the fill line) put the cap on
Start with passenger rear, crack the bleeder screw, then tighten it.
put the vaccum bleeder on the bleed screw, create vaccum, open bleeder 1/4 - 1/2 turn.
continue to suck fluid until it is clear - if this is the first time you have flushed be VERY careful and check the level in the master often. You don't want it to go much below the "full" line. I've done it a lot so I know how long I can suck fluid out.
Then fill master, do the driver rear, passenger front, driver front.
You will use almost the whole quart!
Then have a helper do the traditional method of slow easy pumps on the brake pedal till hard, crack the bleeder screw, when pedal is on the floor close the bleeder screw
I repeat this between 3-6 times for each caliper. Check the master after each caliper!

Wildride

I believe if you draw a schematic of the brake lines you will find the right front wheel is furthest from the master cylinder, then the left front and a tossup between the rear wheels.

The fluid goes from the master cylinder back to the ABS controller (behind the seats) then to the various brake cylinders.

This is contrary to the traditional brake line setup which didn't have ABS.

timmy 93

I bought two speed bleaders.Did the back then the front.I replaced the old fluid with Valvoline Syn Tech made a big difference. Tim

samsonb

Yeah, thats the way I'm gonna flush mine next. As I believe it was posted from the service manual somewhere here about which order to flush when you have ABS.

tombrammer

Thanks! It sounds like the FSM is telling you to remove the clutch actuator from the clutch housing and hold it horizontal with the bleed nipple facing up, is this really necessary? If someone is pressing the clutch pedal and then you open and close the nipple why do you need to turn it up? Am I missing something obvious here?
I got the brakes flushed, took forever pumping the pedal a little so as not to damage the o-ring.
The fluid in my clutch reservoir looks like the worst gunk I have ever seen, all I did for now was to empty the reservoir and refill it, but I really want to flush it completely. Can I replace the nipple with a solo brake bleeder?
Also I bought 4 earl's solo brake bleeder from summit and they worked great, but next time I am buying a Motive pressure bleeder.

94z07fx3

Air bubbles up. A bleeder at the bottom will only bleed fluid not air.

The thing is though that these master and slaves are supposed to be self bleeding. I used a vacuum pump and held the slave upside down and pumped the resevoir dry in only a few pumps and had to do it all over.

When I was done I did a bit of reading and some people were reporting that to bleed the system you only had to make the installed slave level with jacking the car and then operate the clutch pedal 50 times slowly to bleed all the air out of the slave. This makes sense to me since the line in is the highest point when the slave is level. YMMV

tombrammer

If you want to bleed air I can understand your point but I don't have air in the system only dirt and crud, so I am thinking that I don't need to worry about taking the slave off and holding it however (nipple up), for what I am trying to do wouldn't it be just as good to leave it where it is and pump the clutch, hold it, open the bleed valve, close the valve, release the clutch and then repeat until clear fluid comes out. I think I am right about that but just want to make sure with some of you who have done this and know.

dogfish246

I am going to change my brake fluid also... So let me see if I understand this:

I am going to use my vacuum tool that pulls oil out of boat engines and slip it over the bleeder screw on the brake.

1.) start with the passenger front wheel
2.) start bleeding the brake with the master cylinder cap off making sure the fluid level doesnt get too close to the bottom
3.) when it does fill the master cylinder with new fluid (does the new fluid mix with the old or will it float on top of it?)
4.) when you see the fluid go clear at the caliper then that wheel is bled
5.) repeat at each wheel going from the front passenger to the rear passenger, then the rear driver, then finish at the front driver

Did I miss anything?
How do you make sure you get a full flush and leave no residual fluid (or very little because there will always be some)
Can you just suck all of the fluid out so it is dry and put the new brake fluid in and bleed it?

Thanks

primalurges

Airmotive sells a power bleeder for about $65 that will give you a full flush in about 30 minutes, did mine last week. Use a turkey baster to remove as much fluid as possible mc and start with passanger rear, driver rear, passanger front, and drivers front.

94z07fx3

Sounds like a good plan.

1. Nope. You've got it.
2. As you said, there will always be a trace of the old left behind.
3. Yes you can but that would involve the more complicated bench bleeding of the master cylinder and would still not remove the trace of old in the system.

FC92

I just did this flush on my 92. I used a vacuum pump, but one thing I noticed was that the MC volume never seemed to go down.
I would fill it up way over the full line, and it seemed to burp a bit then go down to the full mark, but never dropped below full.
I kept filling it with fresh fluid during the flush.

So I put it all back together (no brake issues before the flush, just dirty fluid), and the pedal is mushy, goes to the floor and brakes are lousy. I never touched the abs bleeder behind the seat.

Obviously I got air in the system, but not sure how.

Any ideas?

ittlfly

Sounds like you got air into the system..You can go back to the old fashion way of bleeding.... using a helper to push on the pedal while you ''work'' the caliper bleeders (in the correct order). That should end your air problem if done correctly.

STL94LT1

Where did you find this, Harbor Freight?

FC92

tombrammer - My 92 FSM says the bleeding order is: RR, LR, RF, LF

jaa1992

Yep, I've had it for a couple years now. Makes the flush on the 92 and the wife's 04 easy peasy.

FC92

Had to cycle the ABS module with the scan tool while I was bleeding the system to get all the air out.

Have no idea how I got air in system to start with.

SJW

What scan tool did you use that gave you that capability?

Live well,

SJW