I just converted my drum brakes to disc brakes, and my car stops really weak. All new pads, and I took them apart and cleaned and lubed them back up. I have all the parts out of a 90 iroc including the prop valve for the disc conversion. If I jack the car up on our lift start it up and put it in gear with the tires spinning at idle, and apply the brakes it will slow the tires down but will not completly stop them. Is this normal or is something elese wrong? I also gravity bled them running almost a full big botle of dot 4 fluid through them. Any help would be much appreciated, as money is tight so a shop just aint gonna happen, and I would rather learn to do it myself. in advance.

Mark

 

has it gotten any better?
usually you can expect some "weak or no" brakes right after a caliper has been compressed if you did not "pump" them up before you drive. I have seen master ASE guys drive through bay doors because they forgot to do this...
But otherwise 2-5 brake pedal applications they should be fully pumped out and fully grabbing.

Now on mine I recently took them apart (because I had the same symptoms) to find yet another privious owner f*ck up where one caliper was locked completely, the other barely moved.
Externally they looked fine, other than the completely locked one the bleeder screw was seriously mangled and could not be turned.

If you get the chance slide the calipers back and pull the pads and verify that the caliper moves when you hit the brakes. If not, welcome to my world and be ready to fork out about $150 for new ones (lifetime warranty though).

 

If calipers are the issue get a kit and do a rebuild. Bleed the system again also and be positive the air is purged from the system...sounds like air...do the front brakes feel firm as before the new calipers?

 

I took it all apart and cleand and lubed them. It only seems to be the driver side. It's like the rotor is hitting the part of the caliper where the brake pads sit. I pumped them 10 time before I drove it home about 35 miles. It's a little better but not much, and when I make a left hand turn I can hear the rotor scraping on something. I double checked every nut and bolt, and nothing was loose. The flippin car stoped better with the drum brakes!!!!! I just gotta be patient and it will work out especialy with the help from the people on this board. I will keep looking for everyons ideas, and thanks in advance!!!! Mark
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Net_coma the fronts feel like they are doing most of the work like 90%. The only thing I didn't replace was the master, I know their the same but the fluid was kinda nasty, and had a little black gunk at the bottom of the res. Thanks for the response Mark

 

If the rear discs are PBR's, check "free travel".

JamesC

 

James c,

will check that out this morning, and

 

O.K. guys I have found the problem. I just had the rearend rebuilt, including new axels. Thats when all my problems with noisy brakes started, it turns out that the superior axels that were used are for drum rears and not disc rears. Theese guys knew they had a problem with their axels when they shipped them to us. The guys that does all my rearend rebuilds said the guy said F#*! not again!!!! We ended up shimming the caliper out .60 so it wouldn't rub on the bracket. He orderd me a set of dutchman axels which are the company that make all the axels for Moser. Cool deal for me!!! Thanks for all your help!!!!