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Chevy Blazer GMC Jimmy Maintenance and Repair

3674 messages,  Last post on May 10, 2013 at 1:58 PM

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Messages Page 216 of 368

#2147 of 3674 Brake Problems 1999 Chevrolet Blazer by mitch66

Apr 11, 2006 (3:04 am)

I have a 1999 Chevrolet Blazer that has braking problems. When I apply the brakes I get a crunching/moaning sound mixed with an ABS type feel. The more frequent the braking, the worse the problem. Just last week, I applied the brakes and didn't think they were going to work. I had my foot pressed all the way down. It finally stopped. The pads & rotors are fine. No ABS Lights and no leaking fluid. Your immediate help is needed. Several times I've brought it to the shop for concerns and they say they found nothing. Oh there is a problem, so please help.

#2148 of 3674 Re: 2000 Blazer Fuel Pump Problem [repairdog] by mwhite1

Apr 11, 2006 (4:47 am)

Replying to: repairdog (Apr 10, 2006 8:56 am)
I don't know if I don't understand how it works, but why did it run when it was out of the tank and there wasn't any pressure, but when I put it back in the tank and re-installed the tank it wouldn't run.

#2149 of 3674 Re: 2000 Jimmy stalls after warming up [mrs052502] by repairdog

Apr 11, 2006 (6:30 am)

Replying to: mrs052502 (Apr 10, 2006 5:09 pm)
Fuel pressure was tested with the correct readings I have to assume then. So, have you had the battery and alternator tested if the volt gauge isn't reading approx 14 when running? The battery could be failing with internal shorts and/or failed cells. Blazers get strange without correct voltage - could effect other systems. Any work done recently to the Blazer? No SES light on?

#2150 of 3674 Re: Brake Problems 1999 Chevrolet Blazer [mitch66] by repairdog

Apr 11, 2006 (6:41 am)

Replying to: mitch66 (Apr 11, 2006 3:04 am)
I would take it to a Chevy dealer and leave it till they determine the cause - for your safety and others.
If in the brake system, it sounds like a bad master cylinder, possible power brake booster leak (is the hose from it to the intake manifold good, rubber gromet good, and the connection not leaking - also the intake connection is a housing that can rotate and disconnect). This needs to be seen to determine the cause. ABS module defects should show codes with the ABS light on and using an ABS reader. As a last thought, look at the flex hoses on all wheels and see if when the brakes are pushed any have a bulge or bubble - you stated no leaks in any lines so the reservior should be full and not dropping.

#2151 of 3674 Re: 2000 Blazer Fuel Pump Problem [mwhite1] by repairdog

Apr 11, 2006 (6:48 am)

Replying to: mwhite1 (Apr 11, 2006 4:47 am)
Not sure how you tested it but my guess would be a ground or bad connector. It has a motor in it so possible dead spot in it on the windings. Cheap plastic crap is what I always say to myself working on my 4 Blazers. The big question is does the new one work correctly!

#2152 of 3674 Re: Brake Problems 1999 Chevrolet Blazer [repairdog] by mitch66

Apr 12, 2006 (7:32 am)

Replying to: repairdog (Apr 11, 2006 6:41 am)
Hi RepairDog:
 
I have an update. I will be sending the vehicle to the shop on friday. In addition to your thoughts above, I did notice that when the brakes act up, you can also hear on the left front side a ticking sound that is in sync with the pulsation feeling I'm getting on the brakes.

#2153 of 3674 Re: Brake Problems 1999 Chevrolet Blazer [mitch66] by repairdog

Apr 12, 2006 (9:35 am)

Replying to: mitch66 (Apr 12, 2006 7:32 am)
I went out and looked at my 99 and you have the Kelsey-Hayes 4WAL system located on the drivers side under the hood (black cover with name on it). Looked up some info as follows:
 
From- Motor:The nuts & bolts of Kelsey-Hayes 4WAL, Jun98
By- Black, Ludlow
(partial test only from a longer article)
Used on millions of GM trucks through the years, this antilock system can be a handful to diagnose and service for the uninformed. Here's how to avoid the pitfalls.
 
The Kelsey-Hayes 4WAL ABS system has been used on many GM light trucks through the years. So chances are pretty good you'll tangle with one real soon. Like all ABS, the 4WAL system is designed to keep the vehicle under control during heavy braking. To meet this challenge, however, there may be some sacrifice in pedal feel and even increased stopping distances under certain conditions. Make sure your customers know this and understand what to expect from the system to prevent you from wasting hours trying to diagnose something that may be perfectly normal.
 
The 4WAL system is nonintegral, meaning it uses a conventional booster rather than a separate pump to provide power assist. As a result, there is no external accumulator to worry about, and the pressures you are exposed to during service and repair are the same as with conventional brakes.
 
The Electronic Control Unit (ECU) of the 4WAL system is attached directly to the business part of the system-the Brake Pressure Modulator Valve (BPMV). This assembly can be found under the hood on the right side on pickups, Blazers and Suburbans; beneath the brake booster bolted to the firewall on Astro/Safari vans; and under the vehicle about a third of the way back on the passenger side on G-series vans.
 
System Operation
 
The 4WAL system has three channels of control-right front, left front and rear axle. Although some applications have four wheel speed sensors, if one rear wheel locks, hydraulic pressure to both rear wheels will be reduced. This method of control is not as inefficient as it may seem, since the front wheels do as much as 80% of the work during heavy brake application.
 
The 4WAL system is an active system, meaning it's able to provide energy to reapply the brakes after pressure is released. The vented fluid is stored in accumulators within the BPMV and pushed back to the wheels by an electric pump. Be aware that the solenoids and pump motor can consume up to 45 amps during use, so don't forget to check out the battery and charging system as part of your diagnosis.
 
Self-Tests
 
Two different self-tests are performed whenever the vehicle is started. The first happens as soon as the key is turned on. During this period, the red BRAKE and yellow ANTILOCK lights will come on for 2 seconds. The ECU then tests for continuity in the wheel speed sensor circuits and for proper voltage in the pump circuit. The ANTILOCK light should turn off if no electrical faults are detected; the BRAKE lamp will stay on if either the parking brake is applied or there's a hydraulic problem in the brake circuits.
 
Once the vehicle is moving and the brake pedal is released, the BPMV is tested hydraulically by the ECU. This testing includes the pump and the control valves. The wheel speed sensor inputs are also dynamically tested at this time. If no faults are found, the 4WAL system is operational for the rest of the trip or until a fault is detected.

#2154 of 3674 wheelbearing nut torque by mslough

Apr 12, 2006 (2:37 pm)

what is the ft lbs torque for 2000 jimmy 4x4 wheel bearing hub

#2155 of 3674 Re: Brake Problems 1999 Chevrolet Blazer [mitch66] by mitch66

Apr 13, 2006 (2:47 am)

Replying to: mitch66 (Apr 11, 2006 3:04 am)
Excellent information. I just printed the entire article out and will give it to my tech. It has to be the ABS system. It all points to that. You are good !! I will definitely keep you in the loop on this. I've already recommended this site to co-workers !! My brakes are 70% of the time acting like they need ABS when they don't (dry pavement/normal stopping. I've owned the vehicle since day 1 and know what's normal and not and this is not. Thank you for everything to date.

#2156 of 3674 Re: wheelbearing nut torque [mslough] by repairdog

Apr 13, 2006 (3:48 am)

Replying to: mslough (Apr 12, 2006 2:37 pm)
99up is 103 ft lbs per Hayes (98 and earlier is 180) for the CV axle hub nut (big 36mm one). The hub attachment bolts that are 18mm (hub to steering knuckle) are 77 ft lbs.

Messages Page 216 of 368

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