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david craig
david craig, Auto Mechanic
Category: Chevy
Satisfied Customers: 3102
Experience:  owner/mechanic at 3D Automotive
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I am having a couple issues, 2005 chevy express 3500, yes i

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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....
Customer: replied 7 months 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

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 7 months ago.
haha which one do we have a better chance of solving? I guess I would like to diagnose the brakes

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

Customer: replied 7 months 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?

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

Customer: replied 7 months 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 7 months ago.
loosened
Customer: replied 7 months ago.
the engine was running

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

Customer: replied 7 months ago.
discs all around

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

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 7 months 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.

replace the master cylinder.

Customer: replied 7 months ago.
on all 4 discs? or up by the reservoir

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

what engine do you have in that? 6.8?

Customer: replied 7 months ago.
6.0L I believe

sorry, that what i meant. ok. thanks

heres a pic

Customer: replied 7 months 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 7 months ago.
would that also be what is causing the ABS light to be on?

the seals inside the master cylinder appear to be bad.

Customer: replied 7 months ago.
I read somewhere that it has some sort of booster that works off of the power steering fluid?

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.

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

Customer: replied 7 months ago.
Ok... When I change this out tomorrow can I just respond back to the thread? How long do I get with you?

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

Customer: replied 7 months ago.
man thats awesome... Thanks for your help. I will get this swapped out tomorrow
Customer: replied 7 months 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

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

let me have your vin. maybe i can find out

Customer: replied 7 months ago.
1GAHG39U851232667

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

Customer: replied 7 months 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.

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

Customer: replied 7 months ago.
I found the identification plate after some googling... I have JL4, so I think it means that I do have active brake control

yep. thats what that means

Customer: replied 7 months ago.
Do you know the torque specs for the bolts that hold it on?

the master?

hang on a sec.

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.)

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 7 months ago.
Didn't really have anything to cap the brake lines with. I can just run all new fluid through it afterward though right?

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

Customer: replied 7 months ago.
Am I supposed to leave these blue caps on the bleeder valves? I'm not huh?
Customer: replied 7 months ago.
I have been pushing the rod in withthem on
Customer: replied 7 months ago.
I'm probably supposed to do it with the tubes attached and in the fluid

yes

you leave the plugs in and use the tubes

Customer: replied 7 months ago.
the other end into a container with fluid?

pull up a you tube video on bench bleeding

yes

Customer: replied 7 months ago.
Am I supposed to bleed with it running?

thats the best way

Customer: replied 7 months ago.
Well I just bled it with it not running. Pedal is still going to the floor
Customer: replied 7 months ago.
Any ideas? When I bench bled the cylinder I had no air bubbles coming through the tubes
Customer: replied 7 months 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?

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

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

Customer: replied 7 months ago.
Rubber break hoses seemed fine and I didn't see any leaks when bleeding

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 7 months 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 7 months ago.
I guess if I can't get rid of the black then I know I need hoses

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

that is true

Customer: replied 7 months 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

ok. good idea.

Customer: replied 7 months ago.
Ok. No air in the lines. New fluid is in the line with no contamination. Still soft
Customer: replied 7 months ago.
Still goes pretty deep into the pedal also

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

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

Customer: replied 7 months ago.
A little yes
Customer: replied 7 months ago.
No problem. I'm leaving for work in 30 min

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

Customer: replied 7 months ago.
Ok... power steering fluid is low. About half way up to the full line
Customer: replied 7 months 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 7 months 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

the hydro boost init has residue?

Customer: replied 7 months ago.
did the old master cylinder... not like dripping wet but kinda powdery/liquid mix. It's black

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

Customer: replied 7 months ago.
Well it wasn't stuck to it or hard to get off but yes. Once I removed the bolts it pulled right off

ok. let me look into this a bit

Customer: replied 7 months ago.
Ok
Customer: replied 7 months ago.
With he YouTube videos I have watched it does kinda seem like brake booster may be bad

hydro boost or the vacuum booster?

Customer: replied 7 months 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.

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

Customer: replied 7 months 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 7 months 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

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 7 months ago.
what do you recommend?
Customer: replied 7 months 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?

junkyard/salvage yard.

Customer: replied 7 months 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?

no!!!!!

hydro boost..power assist

Customer: replied 7 months ago.
Ok so not the unit behind the master cylinder?

it looks like this

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

Customer: replied 7 months ago.
Where is that located in the vehicle?
Customer: replied 7 months ago.
Looks like the thing against the firewall that the master cylinder is bolted too.
Customer: replied 7 months ago.
Ok he said that's what he quoted me for
Customer: replied 7 months ago.
34;Hydro assist brake booster" were his exact words
Customer: replied 7 months ago.
if that is correct I'm going in the morning before work

yep then thats correct

Customer: replied 7 months 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

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 7 months ago.
Ok I have a buddy coming to help me tomorrow... any special tools needed?

nope, just regular ole bleeding tools

Customer: replied 7 months 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

ok my friend

Customer: replied 7 months 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 7 months ago.
Says 2005 express is on the list
Customer: replied 7 months ago.
Dang... never mind. My vin is not within the range haha

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

Customer: replied 7 months ago.
Ok

any update?

Customer: replied 7 months ago.
Not covered under recall. I'm gonna call napa tomorrow and order one I guess
Customer: replied 7 months ago.
Talked my buddy that is going jeep riding with me this weekend into pulling it haha so that's a plus too!

ok my friend. keep me posted

Customer: replied 7 months ago.
Will do. Thanks!

you bet

Customer: replied 7 months ago.
Brake booster should be in tomorrow. Just wanted to give you an update!

thnks bud.

Customer: replied 7 months ago.
Pretty sure this is it

yes sir

Customer: replied 7 months ago.
Any idea how much power steering fluid I need to pick up on the way home?

get 2 qts.

Customer: replied 7 months ago.
Thank you sir

yepper

Customer: replied 7 months 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?

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

Customer: replied 7 months 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

bleed it again and again if you need to

Customer: replied 7 months 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

bleed the brakes again with the engine running

Customer: replied 7 months ago.
Gonna try to get it all bled good this weekend. We are in south MS and it decided to get colder than a witches teat the last few evenings. Im not used to that haha

ok my friend

Customer: replied 7 months ago.
Bled the brakes 2 more times and had to add a little more power steering fluid. I feel like the brakes are softer than the other day.

how soft is soft?

Customer: replied 7 months ago.
Well going down it has some resistance but it comes up real slow
Customer: replied 7 months ago.
I feel like the power steering pump is a little louder than it used to be. But I could just be paranoid about it now.

drive it around for a while. it may straighten itself right out.

Customer: replied 7 months ago.
I added some power steering fluid and it got a lot quieter. For real? Haha

for real, drive it around? yes.

Customer: replied 7 months ago.
Well I drove it around. I guess it is as good as it gets maybe haha. I used to drive this every day but I bought a little Mazda to use to save gas. So maybe I've just forgotten what it felt like and I'm spoiled by my car. Even hooked my jeep up on the trailer and pulled it around. It stops for sure but still maybe a little soft. Also still a slow return on pedal but not terrible. Maybe this is good

i believe it will get better the longer you drive it. seen it happen so many times.

please accept the answer and leave a 5 star rating for me if you were satisfied with my assistance. thanks my friend. have a great weekend

Customer: replied 7 months ago.
Ok I will for sure! Thank you so much for all of your help. If it doesn't get much better could the power steering pump be bad? That's about the only thing left in the system that we did replace right? Steering feels a little hard maybe is why I was asking. And since the hydro boost thing uses the power steering I thought that seemed logical?
Customer: replied 7 months ago.
ABS light is still on too

you need to have that code erased for abs. if it comes back then you need to have the abs module scanned to see whats turning it on. as far as the power steering pump, if it aint whining it aint bad

Customer: replied 7 months ago.
It was pretty loud. I added fluid and it helped some. Hypothetically if it was bad would it effect the brakes? How do I have the code erased?

yes it would affect the brakes. and you need to erase it with a scan tool

Customer: replied 7 months ago.
Ok... well if it doesn't improve I may change that as well.

ok, my friend.

david craig and 6 other Chevy Specialists are ready to help you
Customer: replied 7 months ago.
Thanks for your help!

you bet

thanks