1997 Pontiac Grand Am

Tiny
ITSME7UP
  • MEMBER
  • 1997 PONTIAC GRAND AM
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 20,000 MILES
I have the Grand AM SE model. I am having brake-fading all the way to the floor at stop signs, and lights, or just slowing down. I have no noise from the brakes, no warning lights, no apparent leaking from the brake fluid reservoir. I am able to eventually put it in Park to keep from rolling further. The ETS stays on all the time. I have taken it to two different chain brake-specialist stores and they both say my Master Cylinder is leaking and one of them said my Master Cylinder and ABS Module are an all-in-one unit, and it appears that way because I see no bolts holding them together but there are a couple rubber lines between them. I called a Pontiac dealer Service Manager and he said he hadn't heard of that before. I am afraid of driving it to too many repair places to get a third, and fourth opinion because of a possible accident. The brake-specialist stores say that my brakes appear to be ok. I have researched, online, the Master Cylinder for my car and saw no all-in-one units. Have you ever heard of this unit, and from the info I have mentioned, does it sound like it is the Master Cylinder that is the problem?
Friday, February 29th, 2008 AT 1:56 AM

7 Replies

Tiny
PEAR69
  • MECHANIC
  • 1,482 POSTS
Is the master cylinder filled up with fluid? You say that there is no apparent fluid leaks so I am assuming that the fluid reservoir is full. If the reservoir is not full then fluid is leaking. This does not mean that the master cylinder is leaking. There are many other causes for brake fluid leaks. To test the master cylinder requires a little mechanical knowledge and patience. If you want to test the master cylinder let me know--if not you should take your car to a dealers service department. They will be a little more expensive than a "brake specialist" but they will also know what to look for and they have more knowledge of your cars specific brake system problems. It is worth it--trust me.I have never heard of a master cylinder being one unit with an ABS module. ABS modules are very expensive to replace and rarely fail--master cylinders are not. This is why they are seperate! Sounds like the "brake specialist" is taking you for a ride.
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Friday, February 29th, 2008 AT 2:32 AM
Tiny
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Yes, the fluid level has always remained full. I check all my car's fluid
levels every week even though I only drive about 60 miles per week. I have
been told that the reason the fluid level is always full, but still leaking,
is that the fluid is bypassing a valve or piston or something like that. I
have noticed that if I pump the brakes I get a firm pedal for a while. I
checked prices for my car's master cylinder at all Major parts stores, and
online, and they are $39 (reman)-$99 (new). I called the parts dept at a
dealer and they quoted a price of $500 just for the part. I also researched,
online, for my car's ABS Module and saw none that looked like mine. I am
hoping I didn't get an experimental GM master cylinder/ABS Module unit when
I bought the car new.
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Friday, February 29th, 2008 AT 11:12 PM
Tiny
PEAR69
  • MECHANIC
  • 1,482 POSTS
I looked at a factory diagram of your mastercylinder/module. Your master cylinder looks to be one unit with the module-- but it is not. The two tubes you described go from the master cylinder to the module--they are very short. These tubes are nothing more than 2 seperate brake lines--one for the front and one for the back. They also should be detatchable when replacing the master cylinder--if not then I cannot imagine that they would be too expensive to replace with new ones.
The master cylinder connected to the brake booster (the big round thing) with two nuts. It is also mounted directly to the module by one or two through bolts. The through bolts are inline with the two small tubes. Look close, this is why the module and master cylinder seem to be one unit. If you purchace a new or remanufactured master cylinder and match it up you will see.
A reman. Master cylinder from CARDONE are the best and usually better than new. Do not buy from any other reman. Company. If a CARDONE reman. Is not available, get a new one.
Gm does not send "experimental" brake systems out to production. LOL
Yes, the brake fluid is blowing past the seals inside of the master cylinder. This is why you must pump the brakes to get a full pedal.
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Saturday, March 1st, 2008 AT 5:46 AM
Tiny
PEAR69
  • MECHANIC
  • 1,482 POSTS
Also, this master cylinder must be bled on the car--not bench bled--and there are two through bolts that hold it to the brake module. When you buy the part and take it to a mechanic he or she cannot give you any BS about replacement parts.

BTW- beware of a mechanic that says that the master cylinder and the module must be replaced as a unit. In my opinion, they just want to get their hands on a perfectly good module and fix it up and sell it to the next sucker--DO NOT BE A SUCKER.
I hope I helped. Good luck and let me know how you make out. If you attempt this repair I will do my best to help.
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Saturday, March 1st, 2008 AT 5:57 AM
Tiny
ITSME7UP
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On Monday I went to the nearest NAPA Auto Parts store and asked for the CARDONE Remanufactured Master Cylinder for my car. They told me they would have it delivered Tuesday. I picked it up on Tuesday. I looked at the box, and part, and did not see "Cardone" on either. I asked if this was a CARDONE one and she said yes. I am skeptical.
You mentioned to have the Master Cylinder bled on the car, should they also bench-bleed the rest of brake system?
I have an appointment to have the part installed Thursday.
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Wednesday, March 5th, 2008 AT 1:59 PM
Tiny
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I am unable to take a picture of the master cylinder on my car but I found one online. There is the silver master cylinder, then a part, the same color, as the master cylinder sitting right next to it on the right that might be the ABS Module and has 4 lines coming out of the top of it, and then a dark gray part sitting next to that part. There are no visible pass-through bolts on the one on my car unless the bolt heads are between the possible ABS Module and the dark gray part.


https://www.2carpros.com/forum/automotive_pictures/163645_MC_3.jpg

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Wednesday, March 5th, 2008 AT 5:47 PM
Tiny
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I got my Master Cylinder replaced today and everything seems ok. They had to completely dismantle the ABS Module to replace the MC. Thank you very much for all your help and advice and info. With everything I have learned about master cylinders, I should be ASE certified. Thanks again.
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Thursday, March 6th, 2008 AT 6:05 PM

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