Posted by Bob Elfstrom on April 08, 1999 at 02:20:53:
In Reply to: Brakes.... posted by Vickye on April 06, 1999 at 12:09:29:
: Ok, so here is my rather ignorant question. What exactly are good brakes supposed to feel like on a
: Suburban? What I have noticed is that my brakes feel soft. I didn't really notice how soft until I drove a
: different car and nearly embedded the steering wheel in my chest when I braked to slow down, not stop
: ... which I did non-the-less. I realize the thing weighs a ton, but with all this brake talk, I am getting a
: little nervous. Also, is there a way to improve brake performance without voiding warranty>??
: P.S. Yah I just bought the Beast, no I have never driven such a big car before, yes I expect it to
: handle like a sportscar... that outta cover the smart you know what responses.
To bad this thread doesn't have a FAQ to keep the discussions on these types of questions easily available, but here is a "condensed" version.
A Suburban takes around 160 ft. to stop from 60 mph. A good performance car will do it in around 130 ft. and the all out cars (Vettes, etc.) will stop in around 120 ft. As a minimum, your Sub will take 20 ft. longer to stop than the Honda in front of you.
The "feel" of the brakes on the Suburban (especially 1/2 ton, the 3/4 ton feels better because of use of hydraulic booster from the power steering pump) is soft or mushy and you feel like you really have to get a lot of pedal pressure before something starts to happen. There are some things you should check to make sure the system is operating properly, then it can be improved.
1. MAKE SURE the rear brakes are properly adjusted (and check the adjusters). The Sub has over 50% of it's weight on the rear end, which simply means the rear brakes have a larger share of the stopping chores than a lot of people expect.
2. There is a TSB about pulling to one side and poor brake pad life that replaces shoes and pads with different material and replaces the proportioning valve
3. Depending on age, the caliper bolts may not be allowing the caliper to move properly to provide even braking pressure. (This will result in poor stopping, and uneven pad wear).
Now if all of those things (and your ABS system) are fine, my recommendations (based on personal experience) are the following:
1. Use a Kevlar/Carbon matrix pad (and shoes!) by Praise Dyno or Porterfield (you won't find these at Pep Boys). Won't fade easily and have 50% higher coefficient of friction than stock.
2. A lot of the "soft" comes from the expansion of the rubber brake hoses as you apply the brakes. Russell makes DOT approved Stainless Steel braided Teflon hoses that DO NOT expand, so that pressure goes toward braking force.
3. Flush your brake system COMPLETELY if the fluid is more than two years old. The brake fluid adsorbs water and can boil or cause corrosion of brake system parts. A very good fluid with high boiling points and not a high price is Valvoline DOT 4 "SynPower", about $5 a quart.
There are a lot of other high dollar things you can do (how about $5000 for Brembo front discs?). But what I've described will cost less than $300 in parts, you will notice a BIG improvement in pedal feel, and may even have shorter stopping distances. But the Sub will NEVER be as responsive, or stop as short as the sports car you are following, so be careful, the laws of physics don't change. Even the new GM pickups with four wheel disc brakes take around 150 ft. to stop from 60 mph, based on a magazine test I read.
Take Care,
Elf