brakes - 1998 1500

On my truck...'97 GMC 5.7 2wd...I found the adjusters to be pretty weak...my truck has been mushy from day one. Probably the weakest link of an otherwise great truck.

What is the cure if any?

Al S.

I had a 95 Z-71 and the brakes were always mushy but never any kind of road hazard. unlike this 04 3500 I have now, careful or you'll go through the windsheild.. j/k

Have a Great One ! Bob :)

I put on square tires!

no...really!...nah...joshin'...when I change my pads out I just make sure the adjusters are clean and spring tight...that's it...and I have my fat sister sit in the very back of the bed.

I own a 1985 1/2 ton that also has a 350 and power brakes. As "BPJB" says, you are through the windshield if you lay on the brake. But unlike him I feel that the extent of mushiness may in fact create a road hazard. I feel that the breaking distance is increased considerably by the present condition. What puzzles me also is that two mechanics, one a certified GM mechanic and the other an independent have said that this is a common problem with chevy trucks of this era. Yet I have seen no indication of this being a recurring problem in over 20,000 posts in this group. I questioned the independent who had just replaced the very pricey fuel pump module in my truck's tank as to a cure for my problem. He had test driven my truck so he knew what I was talking about. I suggested that the problem might be in the master cylinder and asked about replacing it. he replied that in his experience, replacing the master cylinder was a temporary fix lasting only 2 to 6 months. He also said that it had something to do with the ABS. What do ya'll think???

Al S.

In article , Bob Truck wrote:

Frankly I'm skeptical about the excuse that it's the ABS causing the problem. The ABS only affects the feel of the brakes when it's activated. There are no parts that would allow for extra "give" in the system related to the ABS - in fact, if you disabled the system you wouldn't even notice the difference unless you needed it in a skid braking situation. I've owned an '88, a '95 and now an '04 Chevy full sized truck and I've never noticed anything even remotely like what you are complaining of.

While it is true a weak or leaky master cylinder can cause this problem, there are also other things that you should be looking at besides the ABS.

1. You should have your entire braking system bled, including the ABS module (there is typically a bleeder just for that as well as the ones on each brake cylinder/caliper). If there is any air in the system - including inside the ABS system - you could get enough sponginess to notice. If it's not the master cylinder, this is where the smart money is. Remember, bleed the ABS module first, then each wheel from the closest to the furthest away from the master cylinder in turn. Air can collect in many places like in the proportioning valve, so I would recommend a power bleeder (hand vaccum pump).
2. Inspect for any weak or swollen brake hoses. A weak hose can expand when applying the brakes and cause the same feeling. Consider changing to braided stainless steel flexible lines for the connection between the hard piping and each caliper/cylinder.
3. If you have rear drums, check for proper adjustment, blown seals or excessive play in the shoes. The rear drum brake self adjusters may not be the greatest, but you'd be surprised what a difference a good cleaning and manual adjustment at a shop will do.
4. Make sure you have good quality pads. Some pads are not designed for a heavier vehicle and may feel like you need extra pressure to slow you down because they don't have the friction you need.
5. Check your wheel bearings and axle seals. A leaky seal could let grease or oil get onto the brake disc or drum.
6. Go to another mechanic. There's no reason why a new master cylinder would fix the problem for 2-6 months if there wasn't a problem with the master cylinder to begin with.

Cheers - Jonathan

Thanks. I'll look at all of those things. I am not a certified mech but I've rebuilt several engines (successfully) and always worked on my own brakes, etc. for over 30 years. I am asking the questions because no matter how much experience one seems to have, things change.

Al S.