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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15181
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I am having a couple issues, 2005 chevy express 3500, yes i

Customer Question

Hello. I am having a couple issues
JA: What is the model/year of your Chevy?
Customer: 2005 chevy express 3500
JA: Are you fixing your Express yourself? What have you tried so far?
Customer: yes i have been trying to fix it myself... Two issues: (1) the running light on the rear driver side light isnt working. Everything else works fine. Brakes, turn signal, and reverse light. I did notice that when the turn signal is flashing that the reverse light also flashes
JA: Have you checked the brake fluid? How's the level and when was it last changed?
Customer: i checked all the fuses and took the lights apart and made sure the bulbs werent the issue. I also took apart some of the plastic inside the van so I could make sure the connectors were connected properly
JA: Anything else you want the mechanic to know before I connect you?
Customer: I can discuss brakes real quick....
Submitted: 11 days ago.
Category: Chevy
Customer: replied 11 days ago.
The issue with the brakes is as follows. They have pressure, but go all the way to the floor. The ABS light is on and the pedal seems like I am not getting any assistance. Check the fluid levels and it was very low. Added DOT3 and then bled the brakes. The fluid coming out of the zerk was very dirty. Ran a decent bit of new fluid through and the clarity improved. Pedal has a little more resistance, but still goes all the way to the floor and I have to apply a lot of pressure to stop. Im not exactly sure the issue, but they brakes used to feel great
Expert:  david craig replied 11 days ago.

Hi Im David, thanks for visiting the site. this is a one question at a time site so which one would you like to address first?

Customer: replied 11 days ago.
haha which one do we have a better chance of solving? I guess I would like to diagnose the brakes
Expert:  david craig replied 11 days ago.

were you bleeding the brakes with a helper? and if so did you try bleeding them with the engine running?

Customer: replied 11 days ago.
Is the $26 for the call added onto the $23 that it said I would pay at the beginning? Or is it $26 total?
Expert:  david craig replied 11 days ago.

i didnt offer the call. the site does that automatically. sorry. and yes its an extra 26.00

Customer: replied 11 days ago.
I bled the brakes with a hose dropped into a clear water bottle half way full of fluid. Had a buddy push the pedal down and hold after I loosed the fitting. He released the pedal after I tightened the zerk back up.... Did this 5-10 times on each wheel. No bubbles were appearing in the bottle
Customer: replied 11 days ago.
loosened
Customer: replied 11 days ago.
the engine was running
Expert:  david craig replied 11 days ago.

ok. good. you have rear drums on that correct?

Customer: replied 11 days ago.
discs all around
Expert:  david craig replied 11 days ago.

ok. pump up pedal key off. keep pressure applied. start the engine and trell me how far the pedal goes down.

Expert:  david craig replied 11 days ago.

was any work done to the brakes and thats why you bled them or did it just start going to the floor out of the blue?

Customer: replied 11 days ago.
I do not use it very often. I was hauling my jeep with it earlier in the year and the brakes were just horrible from the start. Had never had issues before that. I am hauling the jeep again this weekend, so wanted to try to figure it out.Pumped the brakes a couple of times and held it. It seemed like it was bottomed out (also the pedal did not want to come up when I was releasing with van off). Cranked van and the pedal did not move.
Expert:  david craig replied 11 days ago.

replace the master cylinder.

Customer: replied 11 days ago.
on all 4 discs? or up by the reservoir
Expert:  david craig replied 11 days ago.

the master cylinder in the engine compartment attached to the brake booster.....do not forget to bench bleed it before installing.

Expert:  david craig replied 11 days ago.

what engine do you have in that? 6.8?

Customer: replied 11 days ago.
6.0L I believe
Expert:  david craig replied 11 days ago.

sorry, that what i meant. ok. thanks

Expert:  david craig replied 11 days ago.

heres a pic

Customer: replied 11 days ago.
ok great. I will try to change that out tomorrow. If that doesnt fix it can I just respond back to this or how does that work?
Customer: replied 11 days ago.
would that also be what is causing the ABS light to be on?
Expert:  david craig replied 11 days ago.

the seals inside the master cylinder appear to be bad.

Customer: replied 11 days ago.
I read somewhere that it has some sort of booster that works off of the power steering fluid?
Expert:  david craig replied 11 days ago.

it can cause the abs light if there is air trapped in the abs module, but its probably a bad wheel speed sensor. we can look at that after we take care of the brakes if the abs light is still on.

Expert:  david craig replied 11 days ago.

yes it has hydroboost. that uses the power steering for brake assist.

Customer: replied 11 days ago.
Ok... When I change this out tomorrow can I just respond back to the thread? How long do I get with you?
Expert:  david craig replied 11 days ago.

yes you can and for as long as it takes to fix the brakes.

Customer: replied 11 days ago.
man thats awesome... Thanks for your help. I will get this swapped out tomorrow
Customer: replied 11 days ago.
I see "with active brake control" and "without active brake control". http://www.autozone.com/brakes-and-traction-control/master-cylinder-brake-system?filterByKeyWord=master+cylinder&fromString=search&isIgnoreVehicle=false&model=master
Expert:  david craig replied 11 days ago.

not sure about that one. they should know at the part store.

Expert:  david craig replied 11 days ago.

let me have your vin. maybe i can find out

Customer: replied 11 days ago.
1GAHG39U851232667
Expert:  david craig replied 11 days ago.

look in the glove box. there should be a sticker in there with a brake code... like JL4 or JF7

Customer: replied 11 days ago.
hmm... I didnt see anything. The only glove box I have is in the dash, down low below the radio, between the front two seats. There was no badge or anything located there.
Expert:  david craig replied 11 days ago.

OK. Ill look tomorrow. its 11:30 gotta get some shuteye.

Customer: replied 11 days ago.
I found the identification plate after some googling... I have JL4, so I think it means that I do have active brake control
Expert:  david craig replied 10 days ago.

yep. thats what that means

Customer: replied 10 days ago.
Do you know the torque specs for the bolts that hold it on?
Expert:  david craig replied 10 days ago.

the master?

Expert:  david craig replied 10 days ago.

hang on a sec.

Expert:  david craig replied 10 days ago.

Brake Master Cylinder: Service and Repair
Master Cylinder Replacement

Master Cylinder Replacement

Caution: Refer to Brake Fluid Irritant Caution in Service Precautions.

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Service Precautions.

Removal Procedure

1. Apply the park brake and block the wheels.

2. Disconnect the electrical connector from the brake fluid level sensor, if applicable.
3. Remove the driver side upper fender support.

4. Important:

Install a rubber cap or plug to the exposed brake pipe fitting ends in order to prevent brake fluid loss and contamination.

Disconnect the brake pipes from the master cylinder.

5. Plug the open brake pipe ends.

6. For vehicles with JL4, crimp the hose (4) at the master cylinder to prevent fluid from leaking out.
7. Remove the clamp (5) and hose (4) from the reservoir. Plug the port in the reservoir

8. Remove the master cylinder mounting nuts.
9. Remove the master cylinder from the vehicle.

10. Remove the master cylinder reservoir.

Installation Procedure

1. Install the master cylinder reservoir.
2. Bench bleed the master cylinder.

3. Install the master cylinder to the vehicle.

4. Notice:

Refer to Fastener Notice in Service Precautions.

Install the master cylinder mounting nuts.
^

Tighten the nuts to 36 Nm (27 ft. lbs.)

Expert:  david craig replied 10 days ago.

5. For vehicles with JL4, remove the plug from the reservoir port and install the hose (4) and clamp (5) to the reservoir.
6. Remove the crimping tool from the hose (4).

7. Remove the rubber cap or plug from the exposed brake pipe fitting ends.
8. Connect the brake pipes.

^

Tighten the pipe fittings to 25 Nm (18 ft. lbs.).

9. Connect the electrical connector to the brake fluid level sensor.

10. Install the driver side upper fender support.
11. Bleed the hydraulic brake system.
12. Release the park brake and unblock the wheels.

Brake Master Cylinder: Service and Repair

Master Cylinder Bench Bleeding

Master Cylinder Bench Bleeding

Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or
equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid,
may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

1. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.
2. Remove the master cylinder reservoir cap and diaphragm.
3. Install suitable fittings to the master cylinder ports that match the type of flare seat required and also provide for hose attachment.
4. Install transparent hoses to the fittings installed to the master cylinder ports, then route the hoses into the master cylinder reservoir.
5. Fill the master cylinder reservoir to at least the half-way point with Delco Supreme 11® (GM P/N 12377967, Canadian P/N 992667) or equivalent

DOT-3 brake fluid from a clean, sealed brake fluid container.

6. Ensure that the ends of the transparent hoses running into the master cylinder reservoir are fully submerged in the brake fluid.
7. Using a smooth, round-ended tool, depress and release the primary piston as far as it will travel, a depth of about 25 mm (1 inch), several times.

Observe the flow of fluid coming from the ports.As air is bled from the primary and secondary pistons, the effort required to depress the primary
piston will increase and the amount of travel will decrease.

8. Continue to depress and release the primary piston until fluid flows freely from the ports with no evidence of air bubbles.
9. Remove the transparent hoses from the master cylinder reservoir.

10. Install the master cylinder reservoir cap and diaphragm.
11. Remove the fittings with the transparent hoses from the master cylinder ports. Wrap the master cylinder with a clean shop cloth to prevent brake

fluid spills.

12. Remove the master cylinder from the vise

Customer: replied 10 days ago.
Didn't really have anything to cap the brake lines with. I can just run all new fluid through it afterward though right?
Expert:  david craig replied 10 days ago.

yep, but you might have to bleed the hell out of the brakes.

Customer: replied 10 days ago.
Am I supposed to leave these blue caps on the bleeder valves? I'm not huh?
Customer: replied 10 days ago.
I have been pushing the rod in withthem on
Customer: replied 10 days ago.
I'm probably supposed to do it with the tubes attached and in the fluid
Expert:  david craig replied 10 days ago.

yes

Expert:  david craig replied 10 days ago.

you leave the plugs in and use the tubes

Customer: replied 10 days ago.
the other end into a container with fluid?
Expert:  david craig replied 10 days ago.

pull up a you tube video on bench bleeding

Expert:  david craig replied 10 days ago.

yes

Customer: replied 10 days ago.
Am I supposed to bleed with it running?
Expert:  david craig replied 10 days ago.

thats the best way

Customer: replied 10 days ago.
Well I just bled it with it not running. Pedal is still going to the floor
Customer: replied 10 days ago.
Any ideas? When I bench bled the cylinder I had no air bubbles coming through the tubes
Customer: replied 10 days ago.
Just drove it. Maybe just a little better than before. I think it does catch a little higher in the pedal. There was still black crap coming out of the bleeder valves at the discs. Could the contaminated fluid be the problem?
Expert:  david craig replied 9 days ago.

absolutely.... contamination of brake fluid breaks down its characteristics ..........

Expert:  david craig replied 9 days ago.

keep bleeding it. with engine running. what do the rubber brake hoses look like? any deterioration?

Customer: replied 9 days ago.
Rubber break hoses seemed fine and I didn't see any leaks when bleeding
Expert:  david craig replied 9 days ago.

sometimes the start deteriorating internally due to contamination and that allow the hoses to expand beyond normal, hence giving a soft brake pedal.

Customer: replied 9 days ago.
Should I replace them while I'm at it? I'm headed to get some more fluid and try to bleed it again before work
Customer: replied 9 days ago.
I guess if I can't get rid of the black then I know I need hoses
Expert:  david craig replied 9 days ago.

I would, especially with the fluid being as black as you said

Expert:  david craig replied 9 days ago.

that is true

Customer: replied 9 days ago.
Well after I thought about it... the hose I used was black... and there was dirty fluid in the bottle I was using. I figure it would clear up some and didn't so I assumed I was getting dirty fluid. About to try to get a clear hose also
Expert:  david craig replied 9 days ago.

ok. good idea.

Customer: replied 9 days ago.
Ok. No air in the lines. New fluid is in the line with no contamination. Still soft
Customer: replied 9 days ago.
Still goes pretty deep into the pedal also
Expert:  david craig replied 9 days ago.

are you getting any whining from the power steering at all?

Expert:  david craig replied 9 days ago.

ill be back on in about an hour. got to get to my shop.

Customer: replied 9 days ago.
A little yes
Customer: replied 9 days ago.
No problem. I'm leaving for work in 30 min
Expert:  david craig replied 9 days ago.

ok. im going to look into the possibility of the brake assist from the power steering pump.

Customer: replied 9 days ago.
Ok... power steering fluid is low. About half way up to the full line
Customer: replied 9 days ago.
Also there is some residue on top of fuse box and top of fender well. Someone told me once that it was power steering fluid but I don't know
Customer: replied 9 days ago.
After looking up the brake booster, that is what the guy thought was steering components. I knew he didn't really know haha. The booster has some residue on it where it looks like it may have been leaking somewhere. Maybe at the joint where cylinder meets it . Cylinder had residue also
Expert:  david craig replied 9 days ago.

the hydro boost init has residue?

Customer: replied 9 days ago.
did the old master cylinder... not like dripping wet but kinda powdery/liquid mix. It's black
Expert:  david craig replied 9 days ago.

you had to separate the master from the hydro boost unit, correct?

Customer: replied 9 days ago.
Well it wasn't stuck to it or hard to get off but yes. Once I removed the bolts it pulled right off
Expert:  david craig replied 9 days ago.

ok. let me look into this a bit

Customer: replied 9 days ago.
Ok
Customer: replied 9 days ago.
With he YouTube videos I have watched it does kinda seem like brake booster may be bad
Expert:  david craig replied 9 days ago.

hydro boost or the vacuum booster?

Customer: replied 9 days ago.
I was just watching videos on "brake booster". I don't know jack about brakes really other than the basic concept of how they work so I don't know what I'm talking about haha.
Expert:  david craig replied 9 days ago.

when you sit in the van engine off. pump the brake pedal up. do you get full pedal?

Customer: replied 9 days ago.
When I did this last night it seemed like it may be getting a little stiffer but still wasn't full pedal by any means...
Customer: replied 9 days ago.
I live 30 min from a parts store but there is one here in town right by my work. If you think I need to get something from there before I head home just let me know. I'm supposed to be pulling my jeep out of town this weekend, but if i can't get the brakes where they need to be I may have to try to borrow a vehicle or something
Expert:  david craig replied 9 days ago.

this is my thought. i believe the power steering fluid is contaminated and probably messed up the spool valve in the hydro boost unit.

Customer: replied 9 days ago.
what do you recommend?
Customer: replied 9 days ago.
I see where the unit can be rebuilt. Is it better to just get a new one? A new one is about $300. Is this something that would be worth getting from a junkyard or is it common for it to go out?
Expert:  david craig replied 9 days ago.

junkyard/salvage yard.

Customer: replied 9 days ago.
Ok they have the brake booster at my local salvage yard. $60. He said "a regular old brake booster", I assumed that was right?
Expert:  david craig replied 9 days ago.

no!!!!!

Expert:  david craig replied 9 days ago.

hydro boost..power assist

Customer: replied 9 days ago.
Ok so not the unit behind the master cylinder?
Expert:  david craig replied 9 days ago.

it looks like this

Expert:  david craig replied 9 days ago.

if thats what hes talking about then grab it ... thats a good deal.

Customer: replied 9 days ago.
Where is that located in the vehicle?
Customer: replied 9 days ago.
Looks like the thing against the firewall that the master cylinder is bolted too.
Customer: replied 9 days ago.
Ok he said that's what he quoted me for
Customer: replied 9 days ago.
34;Hydro assist brake booster" were his exact words
Customer: replied 9 days ago.
if that is correct I'm going in the morning before work
Expert:  david craig replied 9 days ago.

yep then thats correct

Customer: replied 9 days ago.
Sorry about the confusion haha... I'm pretty handy when pointed in the right direction lol. So once I get the new one put in I will have to bleed it as well? And if so I'm sure this can be found on YouTube
Expert:  david craig replied 9 days ago.

yes. it will need bled.

Service
The hydro-boost in not serviceable in the field. If the unit is not functioning properly, it must be replaced. The replacement process is straight forward, but bleeding can sometimes be tricky. I am offering a choice of techniques in this area. Hydro-boost brake systems are supposed to be self-bleeding, but this does not always prove to be true.

Bleed Technique 1:

1. Replace any hydraulic line showing external damage. Install new seals for all disconnected fittings (as required) and install an in-line power steering filter. Tighten all hose fittings to OE specifications.

2. Flush the entire power steering system using the vehicle manufacturer’s recommended fluid. Fill pump reservoir to the proper level.

3. Disable engine to allow cranking without starting. Block wheels, put transmission in neutral or park and set parking brake, then crank engine 5 to 10 seconds (avoid overheating starter motor).

4. Refill pump reservoir as necessary. Repeat step 3 until level is correct.

5. Enable the engine to allow starting. Start engine and let idle. Slowly turn steering wheel from lock-to-lock a number of times.

6. Turn engine off and inspect fluid level and condition. Add or remove fluid as necessary. If fluid is foaming, wait one hour then recheck level. Repeat step 5 and 6 until fluid level is correct and shows no sign of air problem.

NOTE: Many of you are aware that Ford power steering systems are very prone to air-related problems. The most effective way to remove air in these systems is to apply a vacuum to the power steering pump reservoir. This technique can be used on most power steering systems.

Bleed Technique 2:

1. Remove return line from hydro-boost and plug end with appropriate size plug or bolt.

2. Connect two- to three-foot piece of clear hose to return port on hydro-boost unit. Place end of hose into empty container at least 1 gallon in capacity.

3. Fill power steering pump reservoir with correct fluid.

4. Disable engine to allow cranking without starting. Block wheels, put transmission in neutral or park and set parking brake, then crank engine 5 to 10 seconds (avoid overheating starter motor) while applying and releasing brake pedal slowly.

5. Refill pump reservoir as necessary. Repeat step 4 until no air is seen in return line from hydro-boost.

6. Remove clear hose from return port and reconnect return line from pump.

7. Enable the engine to allow starting. Start engine and let idle. Slowly turn steering wheel from lock to lock a number of times.

8. Turn engine off and inspect fluid level and condition. Add or remove fluid as necessary. If fluid is foaming, wait one hour then recheck level. Repeat step 7 and 8 until fluid level is correct and shows no sign of air problem.

Procedure
Use either of these bleeding procedures whenever replacing or servicing any component in a hydro-boost system. Normal driving conditions will remove air that remains trapped within the system when components are properly installed and there are no flow restrictions in the system. Always refer to the vehicle service manual for specific installation and testing procedures.

Power Steering Flush
In addition to requiring the correct pressure, it is also critical that the fluid be clean. The tolerances in the moving parts inside the hydro-boost are such that only a small amount of contaminates can cause a malfunction. This is especially true of the spool valve. The tolerances necessary to form a metal-to-metal seal are quite small and any contaminates or tarnish buildup can prevent smooth operation of the spool valve. Since the spool valve controls the flow of fluid into and out of the power chamber, it is critical it functions properly.

Any vehicle equipped with a hydro-boost power assist will benefit from a periodic power steering flush. The only thing is you have to perform an additional step to ensure the hydro-boost power chamber and internal parts are flushed. When performing the flush, apply and release the brake pedal slowly to allow the new fluid into the hydro-boost. If you skip this step you will have the large quantity of old fluid in the hydro-boost that will mix with the new fluid once the brake is applied and released a couple of times.

Hydro-boost diagnosis and service is not difficult especially when you know how the system works. Applying this knowledge with a systematic approach will enable fast and accurate diagnosis of these systems.

Customer: replied 9 days ago.
Ok I have a buddy coming to help me tomorrow... any special tools needed?
Expert:  david craig replied 9 days ago.

nope, just regular ole bleeding tools

Customer: replied 8 days ago.
Went to salvage yard this morning. Waited an hour before they got to pulling the part then had to leave for work. They just called and said they didn't have any with hydroboost. Gonna keep looking and may just have to get a new one
Expert:  david craig replied 8 days ago.

ok my friend

Customer: replied 8 days ago.
Just found this... any truth to it? http://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/hydro-boost-recall-those-who-want-know-299548/
Customer: replied 8 days ago.
Says 2005 express is on the list
Customer: replied 8 days ago.
Dang... never mind. My vin is not within the range haha
Expert:  david craig replied 8 days ago.

it might be worth the effort and call the dealer and see if its covered anyway.

Customer: replied 8 days ago.
Ok
Expert:  david craig replied 8 days ago.

any update?

Customer: replied 8 days ago.
Not covered under recall. I'm gonna call napa tomorrow and order one I guess
Customer: replied 8 days ago.
Talked my buddy that is going jeep riding with me this weekend into pulling it haha so that's a plus too!
Expert:  david craig replied 8 days ago.

ok my friend. keep me posted

Customer: replied 8 days ago.
Will do. Thanks!
Expert:  david craig replied 8 days ago.

you bet

Customer: replied 2 day ago.
Brake booster should be in tomorrow. Just wanted to give you an update!
Expert:  david craig replied 2 day ago.

thnks bud.

Customer: replied 1 day ago.
Pretty sure this is it
Expert:  david craig replied 1 day ago.

yes sir

Customer: replied 21 hours ago.
Any idea how much power steering fluid I need to pick up on the way home?
Expert:  david craig replied 21 hours ago.

get 2 qts.

Customer: replied 21 hours ago.
Thank you sir
Expert:  david craig replied 21 hours ago.

yepper

Customer: replied 17 hours ago.
It says to remove the return hose off of the power steering in order to flush the system. How do I know which hose that is?
Expert:  david craig replied 15 hours ago.

one of the ends of the return hose will look like this

Customer: replied 15 hours ago.
I ended up removing the return hose at the reservoir. Hope that was ok. Got everything bled or so I believe. Seems a lot better. Catches earlier and brake bounces back a good bit quicker. Still maybe not as good as it should be, so I may need to bleed something
Expert:  david craig replied 11 hours ago.

bleed it again and again if you need to

Customer: replied 6 hours ago.
Do you think I need to bleed the brakes or the power steering? The pedal still comes back a little slow... way better but still sluggish
Expert:  david craig replied 4 hours ago.

bleed the brakes again with the engine running