smalldog

Hello all. I have a 1993 GS 300 non trac control. my brakes have been soft for awhile. I bleed the system but had no luck. Next I replaced the master cylinder, rear pads and bleed the system again. same think happens. I still have to pump the brakes in order to have pressure. Is there something I'm over looking or should I replace the brake booster? note ....if I plug the valcum line from the brake booster the brakes are nice and hard.

GS300 I6

iTrader: (2)

when you bled your system. were there any bubbles?

smalldog

I'm sure we got all the bubbles/air out the lines. Man I hope it's not the brake booster

plkyone

iTrader: (1)

Sounds like a booster to me! when u changed the master did u drain all the fluid out of the system?

smalldog

No. I only changed the fluid in the reservior. Changing the booster looks like a beast.

"G"

After you had changed out the BMC were you able regain the original back pressure, then begin to feel soft after some time? Or, was the original pressure never obtained? Before you spend a good amount of time and money on "possibly" failing brake booster, I would suggest to start at the top. With the BMC, did you do your initial bleed connected to the system, or do a "bench"? Pockets in the system on some rare occasions can be deceiving! Bleed your lines in the proper order, and don't forget, other than pumping on the B.pedal, have someone continuously monitoring and filling the reservoir. You could also carefully inspect all calipers and lines for leaks and damages.

smalldog

I was not able to obtain the original brake pressure after changing the BMC. The brakes felt the same before and after changing the BMC. I took the car the have the brake system flushed and no luck. $80.00 gone. Maybe I got a defective BMC from ADVANCE AUTO.

zazzn

I have the same issue, ever since breaking open the lines, i've never obtained the same feel I had when I first had the car.

I've bled the hell out of the car and even changed calipers form my aristo to my mk4 NA tt calipers.

Same deal! It can't be the BMC or the Booster can it?! I mean it was fine until I cracked a line.

smalldog

I'm going to replace the BMC and see what happens. I will keep you posted

smalldog

hello gang....I have more info that may help someone help me solve my problem. I notice that when the car is in park/idle and I pump the brakes, the car sounds like it's going to choke/cut off.

smalldog

OK....replaced brake booster and master cylinder and bleed the system and brakes are still soft. WTF I thought the brake system was easy.

smalldog

I notice that when I press the brakes to the floor (on the first try) the rear brakes are grabbing and not the front. Does anyone know if a defective abs system would make the brakes act this way?

smalldog

OK guys. I have some update info for you. Talked with an old school tech (shade-tree) and he told me to unscrew the bleeder screws on the rear brakes until the fluid starts to leak. After that he said to re-bleed the brakes in this order. Rear passenger, Rear driver, front passenger, front driver. He also said to fill the reservoir after bleeding each wheel. This process worked for me. My brakes aren't 100% but much better then before. I'm going to do this process again tomorrow and see if they improve more. Remember my car is a 1993 with 247,489 miles

1stgenvip

cool, I was reading through and was going to tell you about that order. good to see your brakes are working. and thanks for posting up the info.

GS300 I6

iTrader: (2)

first thing you should of done was a complete brake fluid exchange where you remove all of the old fluid and replaced it with the new one. it sounds like your old fluid was too old. I use a power bleeder because it is better than having someone with you pumping the brakes. Also, if you have want a firmer pedal, get SS line. your old ones are probably cracked.