one for the brake experts.

[nc89sho]

to start off, let me say that i am an auto tech. so i know how to repair/bleed brakes, but this one has got me stumped and i'm starting to have thoughts of parting this car out and that's not good. first off this is my current brake setup:

'96 front, 89 rear brakes. stainless steel hoses.

here is the rundown of my situation:

i was bleeding my brakes by myself. (not because i had a problem, just as a preventative messure because i race this car and the brakes get hot.) I was using speed bleaders and after cracking the first rear bleeder screw loose, the brake pedal got crappy. i finished the bleed sequence and after closing the final screw went to check. I had NO brake pedal at all. (brake pedal was high and firm before this. After getting someone to help me, i blead the whole car the manual way and found that one of the rear screws kept emiting air nomatter what. after carefull examination i determined that the bleeder screws were allowing air back in (possibly past the threads.) so.. I went and bought a set of 4 bleeder screws and replaced all of them. after a few more minutes of bleeding all 4 were giving me nothing but fluid. so i go check and the pedal is firm.... Untill i crank the car. with the car running the brake pedal is very spongy and moves over an inch before REALLY feeling the car slow down. if you pushed hard enough it would go past the gass pedal by about an inch. So i continued bleeding, stoped drove it some. blead, wait a couple days blead it again and so on. with NO change in pedal travel.

SO, .. i decide to try changing the master cylinder. can't find one with the 89 configuration of 1 M12 fitting and 3 M10 fittings so i opt for one listed for an SHO at advance wich has 2 M12 fittings and 2 M10 fittins. it was pretty easy to cut off the flare, swap an m12 off the parts car, and bolt everything up. i blead everything out and wound up with the exact same pedal feel.

So i decide just to take them out of the mix (and because a new season is coming up) I replaced the front and rear brake pads, and re adjusted the parking brake cable. Then got ahold of a power brake bleeder and attached it to the master cylinder and after bleeding it in the sequence alldata called for (LR, RF, RR, LF) i seemed to get a small bit of air out. pedal felt better for a couple minutes but after a short trip down the road, the pedal feels EXACTLY the same again.

I'm at a loss..... forgot to mention that this is acctually the third master cylinder i swapped because i thought maybe the second one was defective.

what am i not checking???? is this just the brake system that will never be right again?

oh, and the car still stops, brakes work, just not like they used to, the pedal was never this spongy and non-responsive before.

 

[midnightauto]

I don't do many gen 1 or 2 cars but it sounds like you have air stuck in the system. does the car have ABS

 

[rcsavage]

89's do not have abs.

 

[FREAK_SHO]

Bedded the brake pads properly?

 

[NWGRN94MTX]

I had problems with leaky "Speed Bleeders" also. Big P.O.S.

How are your brake lines?

 

[shopartsnw]

Speed bleeder problems X2 here. THey worked the first few times then they would leak (ever so slightly). I have tried aftermarket bleed screws also and had problems. Can you get a set of used bleed valves from an old set or a junkyard?

So my thoughts:

1) put some stock bleed screws in if you can.

2) I have had a master cylinder go bad after bleeding the brakes before. The slight bit of crud that gets built up at the end of the normal stroke gets into the seals when you bleed the brakes all the way to the floor (dragging the seals past the crud in the bore). So changing master cylinders is a definite possibility. I have had bad remans right out of the box also (A1 Cardone), so you may want to try a different master cylinder. Could it also be the difference between the master cyinder you are running and the 89 model you could not get??? Also verify that you bench bled all the air out of the master cylinder.

3) #3 would have been ABS bleeding, but not on an 89, so at that point I am at a bit of a loss. A bad power brake booster or check valve will also give you strange braking issues, but since you did not mess with that, I would go there last.

4) Look at the banjo bolt connections and bleed screws at each of the calipers. Dry them off REALLY good. Start the car and pump the brakes. The power brakes will generate more pressure than with the car off. Kee pumping until you get the soft pedal and then go looking for the leaks. It does not take a very big leak to make a spongy brake pedal.

If all else fails, follow the shampoo bottle "lather, rinse, repeat". I have found repeat bad reman parts lately, so just because you replace a part, does not mean it is a good part. Start at the top and keep looking. THe only thing I hate worse than chasing a brake problem is electrical gremlins ... and drywall ... and people who litter. Ok, there are a lot of things worse than a brake problem, but I understand your frustration.

Best of luck

Mike

 

[Shoaz]

If you haven't already, check the hoses. Also, is it possible that this is a problem with the booster and/or a vacuum line rather than the brakes? Maybe the fact that it was fine until you started the car was a hint to that effect?

The main problem with speedbleeders (IMHO) is that the sealant goop around the threads dries out and/or just goes away. You can get replacement stuff from them in a bottle that should help any leaking or air injestion, although there is also high-temp teflon-ish pipe-dopey-kind-of stuff that you can get at places like Home Depot that ought to work as well.

I loves my speedbleeders, but you do have to pay attention to the thread sealer.

 

[nc89sho]

car does not have abs. and this is master cylinder 3. first was OEM, second was A1 cardone, and this one is bendix. no change in problem with any. Hadn't really thought about the bleeder screws still being a problem. i'll look into that.

 

[NJSHO]

Ive read that the opposite problem happens when you have a brake booster/vacuum problem ie. pump the pedal hard and when you start the car the pedal is still the same hardness (ie. the pedal should move a little and require less effort to hold.)

Ive seen the bolt that holds the rear parking brake return spring start to leak, are you losing any fluid? As stated already clean everything off very well and recheck that something isn’t leaking. The way I see it, if there was a problem with the master cylinder you would get the problem all the time not just after the car was started. You could also try tapping the calipers/master cylinder with a block of wood to try and get any air that maybe trapped in them and then rebleed.

Did you "bench bleed" the master cylinder?

I thought the proper bleed sequence was to start with the longest line to the shortest: passengers rear, drivers rear, passengers front, drivers front.

Its funny because I had the same exact problem with my car. I must have gone through 5 bottles of fluid trying to bleed the air out. It turns out it was air trapped in the abs system. I know you dont have abs, but it really sounds like air is somehow still in your system.

SHOAZ - do you have to remove the speed bleeder completely to put the new speed bleeder thread goop on? If thats the case, how do you stop the fluid from hemmoraging out while you put the new stuff on and let it dry?

 

[Shoaz]

Ive read that the opposite problem happens when you have a brake booster/vacuum problem ie. pump the pedal hard and when you start the car the pedal is still the same hardness (ie. the pedal should move a little and require less effort to hold.)

I think that's if the vacuum has failed completely. I'm wondering whether there's not something wacky in the booster, but it's just me speculating. I don't know why air in the system would know whether the car was running or not, and that's the only thing that makes me think of the booster.

I thought the proper bleed sequence was to start with the longest line to the shortest: passengers rear, drivers rear, passengers front, drivers front.

It is, but AFAIK there's not a horrible consequence to not doing it that way. I've never really sorted out the rationale for doing it that way.

SHOAZ - do you have to remove the speed bleeder completely to put the new speed bleeder thread goop on? If thats the case, how do you stop the fluid from hemmoraging out while you put the new stuff on and let it dry?

Yes, you need to get it out so you can get at the threads. IIRC, on mine if the cap is on the reservoir it won't leak very much with the bleeder out. If you still have your old OEM bleeders you could just stick one of them in while re-gooping the speedbleeder.

 

[AREA 91]

So you are only getting a spongy pedal when the car is running. Dod you check the brake booster? That will give you a soft/major traveling pedal, with the car running. Also check the rear brake leveling block located by the left rear.

 

[SHOtime2511]

brake booster..?

 

[nc89sho]

todays update:

can't find any leaks at all. had three techs look and noone else sees any either. parking brake was binding mechanically (appears to be inside the caliper.) these calipers are warrentyed so they will both be replaced (rear) tomorrow. after that if there is no change i'm looking at the MC/booster. I have an extra booster here so if i change MC's again i'll swap the booster while i'm at it. any tips or ideas for finding the acctuall correct 89 MC?????

 

[shomesomesho]

any tips or ideas for finding the acctuall correct 89 MC?????

I recently replaced the booster & MC on my '89. Got both from rockauto.

 

[red89mtx]

i had same problem thay had to replace both metal rear lines and re bleed mc was ok eventhough i got another one got it from napa for 50 it was oem setup for the 89 a bendix i think take it to ford they can fix it its easier that way cost me 114 thats it

 

[93rev2sev]

I'm guessing theres a leaky seal in a caliper.

 

[BlackonBlack89]

I recently replaced the booster & MC on my '89. Got both from rockauto.

Was that a PIA??? the booster mostly. it on the to do list but it is at the bottom. i figure after almost 18 years mines gonna need it eventually

 

[nc89sho]

I recently replaced the booster & MC on my '89. Got both from rockauto.

what part number/ brand did you buy for it? none on the site even mention SHO.

 

[Shoaz]

Have you checked the vacuum to the brake booster? It might be worthwhile to make sure the vacuum is working and not leaking before replacing the BB.

 

[rangerj]

If you changed the master cylinder and it is from another model year did you adjust the actuating rod length from the pedal to the master cylinder? The rode comes through the brake booster and pushes on the master cylinder pistons.