Ok, 85 Chevy FullSize Blazer (Suburban) 6.2 Diesel 4x4
I have a Power Steering Assisted Brake system
At low speeds, if I press the brakes, its like they lock up at the press of the pedal. If I'm easy on the pedal and very light, i can usually stop without it just slamming down and almost locking up. When going fast, its fine, just a little different then normal pedal pressure, but at low speeds, if i try to press the brakes its bad, you can feel it kick like it was just slamed and is about locked up. I have bled the brakes 3 times, theres no air in the lines, I'm kinda lost and need some advice.
2007-05-05 05:44:51 · 10 answers · asked by american_muscle_101 2 in Cars & Transportation ➔ Maintenance & Repairs
Hey TXm42, the Hydro Boost unit that sets behind the Master Cylinder was replaced in November when it went bad and I lost almost ALL braking power and Power Steering at 70 MPS on the highway. Is the valve in that or something to be replaced seperately?
2007-05-05 08:37:30 · update #1
i own a repair shop and you need to take the rear wheels off of it and look at the brakes real good if its got shoes on the back of it look at them and see if there worn off uneven or have brake fluid on them,and also look and see if there on right,the little shoe goes to the front always ,and i have seen people cross them before and this will cause that to happen,also look for loose or missing parts,and last but not least,you may have a bad proportioning valve on it ,and this always applies more pressure to the back than the front when it goes bad,that's what it sounds like,and if that is the case you,ll have to replace the valve,that's the only way to correct the problem,good luck with it hope this helps.
2007-05-05 06:16:45 · answer #1 · answered by dodge man 7 · 1⤊ 0⤋
On Hydraulic Boost power brakes there's a valve which controls the flow of line pressure to the actual boost diaphragm.
"Power Steering" Fluid constantly circulates THRU the brake booster under pressure,,,,but it's Bypassed when brake is NOT applied.
When you step on the brake,,,you're actually activating 2 things simultaneously.
1)You are pressing on the actual Master Cylinder which supplies Line Pressure to the Brakes themselves,,,
same as on any old Non-Power Brake system.
2)You're also pressing on the Hydraulic Booster Valve,,,which admits & throttles Boost Pressure to help you press the Master Cylinder.
Your Foot is actually turning the Power Brakes On/Off,,so to speak.
It's a Dual System of Hydraulics---
*Brake Fluid in the Master Cylinder & Wheel Brake Cylinders.
*And, Hydraulic Fluid from the Power Steering Pump which supplies the Brake Boost Pressure.
...............................................................
Here's a data sheet on a Bendix Boost Valve---but this model includes an Electric Reserve Pump.
It's NOT the same as Yours in that respect.
http://www.bscparts.com/pdfs/hydromax.pdf
The Basic Booster and it's valves and controls is Representative of typical Hydraboost power booster.
You can see it's a complicated series of valves,pistons,seals.
It's Generally NOT recommended to try a Do-It-Yourself repair,,,
but to replace the Unit as an assembly.
From the symptoms you describe,,, "over sensitive at low speed",, I'd suspect a "Bad Booster /Valve problem".
You may want to take it to a shop and get a proffesional opinion
Good luck,,,and Be Careful meanwhile
2007-05-05 07:28:28 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Did u modified your brake pump,rotor or caliper to bigger size. Check your brake master cylinder, type of brake fluid dot3 or dot4. I've got a similer problem like yours but size of engine is away small 1.5 lit Proton (malaysian car). Problem solve after change the brake master cylinder because the cylinder piston jammed up. Also check servo vacumn and the hose link to intake manifold.(one way valve hose) Good luck...
2007-05-05 06:14:09 · answer #3 · answered by Anonymous · 1⤊ 0⤋
Sounds like you've got brake fluid leak (or any greasy contamination) on your brake pads or shoes and it is causing them to grab...pull the wheels and spray the pads or shoes down with brake cleaner...can be purchased at a parts store...and try to see if there's a leak in the brake area that needs to be repaired otherwise it will keep reocurring.
Good luck, Paul
2007-05-05 05:52:45 · answer #4 · answered by paul h 7 · 0⤊ 0⤋
Nomadd is ideal, replace the calipers & hardware, you are able to also opt to interchange the rubber brake hoses the pass to the caliper as they could fail internally and reason the caliper to no longer launch. Your truck has rear drum brakes, have you ever checked them?
2016-11-25 20:18:53 · answer #5 · answered by whiten 4 · 0⤊ 0⤋
Check the calipers and see if they are free. If they are not releasing properly they will get hot and tend to grab. I assume the rotors and pads are dry and clean and not soaked with water or oil/brake fluid? If that's not it someone more knowledgeable than me will probably post too.....
2007-05-05 05:51:11 · answer #6 · answered by don3070 3 · 0⤊ 0⤋
Its not your front brakes there is nothing there that would cause that Its in the rear and my guess is something is wrong with the adjusters
2007-05-05 05:57:23 · answer #7 · answered by johnsnyder49090 1 · 0⤊ 0⤋
check the assist sensor but try replacing it because it blazer might not recognize that it is going low speeds.
2007-05-05 05:52:23 · answer #8 · answered by Ted H 2 · 0⤊ 0⤋
try changing your whole brake assembly. rotors, brake pads, calipers, the whole nine.
2007-05-05 05:50:14 · answer #9 · answered by angel p 2 · 0⤊ 0⤋
stop being a lead foot
2007-05-05 05:48:22 · answer #10 · answered by Anonymous · 0⤊ 1⤋