planeguy67

Just finished getting my 1996 C2 on car jacks to do a brake fluid flush. The first thing I noticed was a white wax like substance coating the bottom of the brake reservoir and that little cylinder thingy. I cleaned them out, topped off the reservoir with fresh fluid and hooked up my power bleeder.

I started at the RR outer nipple and only got maybe 5 cc of fluid out, then the flow stopped. Same thing all around the car. I can even remove the bleeder screws and nothing will come out. What the heck is going on??? (my 944 was never this difficult).

Thanks everyone.

jnx

Have the brakes ever been bled?

planeguy67

Not to my knowledge. I bought the car last year with 75k miles. The mechanic who did the PPI mentioned there was no history of a brake fluid flush, so I knew it was due. Seemed strange since the car was well taken care of and in excellent condition.

Do you think all the lines/calipers are gummed up now???

Ray Calvo

Sure you have pressure in the bleeder?

What do you mean by "power beeder"? One of those Motive Products pressure bleeders that connect to your reservoir and force fluid down the lines? If so, try increasing pressure to about 30 psi. If you're using one of these vacuum hand pumps, junk it and get a pressure bleeder; I got blisters pumping those stupid things and brakes never got bled with them.

viperbob

OK, start by removing the bleeder screw, one at a time, and then pump the brake**** warning**** have a rag over the opening. You have a lot of wax crap built up in there so by removing the bleeder screw you can pop that wax plug out of there and then it will bleed normally. Go around the car and do this to all calipers. Then you should be fine.

planeguy67

Thanks gentlemen.

I increased the pressure to 15 psi (had it at 10), opened up one bleeder valve at a time and *gently* pumped the brake pedal about 1/2 way a few times (no, I never floored it). That seemed to force a lot of the gunky fluid out. I went around the car doing that for each screw, let it sit while I ate lunch, and went back.

It started bleeding somewhat normally then, so I went around the entire car using only the pressure bleeder until clear fluid ran out of each valve (slowly, but consistently). Perhaps the fresh fluid helped dissolve some of the waxy crap while I ate lunch??? Then I bled the clutch slave (after a few acrobatic warm-ups) which flowed nicely.

I'll probably let this new fluid "exercise" in the car for a little while and flush it again later this year. Sound like a plan???

Thanks again guys.

BobbyT

When I first got my 993, I put it up on jacks and tried to bleed the brakes with my homemade power bleeder. I couldn't get more than a tiny bit of fluid to come out, so using shop air, I kept jacking up the pressure until the bleeder bottle was bulging. Then I went back to try to bleed again, and heard a "whoosh" from the front of the car. The pressure line had blown off the bleeder, and sprayed brake fluid all over the front end of the car. Knowing what brake fluid can do to paint, I almost had a heart attack. I hosed it off quickly and no harm was done. I think viperbob has the best way to approach this problem...

epj993

I'd follow VBs advice. According to the shop manual (IIRC), maxiumum pressure should not exceed 20psi or you can blow out seals and damage the internals (read: $$$$). 10-15psi should be fine.

viperbob

Bad plan. You already recognize there is a build up in there. Take a few minutes and fix it now. Just do as I described in my previous post. The wax build up is NOT going to dissolve with new fluid (unless you bled with Hydrochloric acid). These are your brakes....... Make sure they are working properly...

planeguy67

Thanks Bob,

I did pump the brake pedal a few times gently and only half way (I didn't want to send the MC piston into uncharted territory). That seemed to remove the restriction and allow me to pressure bleed the brakes normally.

However, I can't help but think there is still waxy residue remaining in the brake system (stuck to the inside surfaces of the calipers, lines, etc.). Since the wax must come from the fluid itself, I imagine it will slowly dissolve over time back into the new fluid. Therefore, I believe the fluid should be flushed again within a year again.

After all, it couldn't hurt.

jnx

I think that is a good idea, Maybe in 6 months or so. Like you said it couldn't hurt., and it should remove some more contaminates.

Martin S.

Power Bleeder with fluid? I just us the power bleeder for air...no more than 15 PSI. I check the master cylinder after each caliper so I don't bleed out the system. I add brake fluid as needed...this way the Motive Power Bleeder stays clean. It works for me!

tj90

I want to add my .02 cents. I used the motive power bleeder and failed to clamp the drain hose off of the MC reservior. I ended up with a can of ATE super blue under the driver side wheel. Make sure you clamp off the drain hose (I used a pair of vice grips).I never had to exceed 10-15 psi to get good flow to all the calipers.

Martin S.

TJ90 writes above, "failed to clamp the drain hose off of the MC reservior." On my 993 master cylinder, the drain hose is blocked off...it looks very "factoryesque"...I will look again this AM, but I have never clamped off this drain. I did have to clamp off the drain hse on a 964...

epj993

I believe the vent tube appeared on '95s but was capped off on '96-98s.