Go Back   AnandTech Forums > Social > The Garage

Forums
· Hardware and Technology
· CPUs and Overclocking
· Motherboards
· Video Cards and Graphics
· Memory and Storage
· Power Supplies
· Cases & Cooling
· SFF, Notebooks, Pre-Built/Barebones PCs
· Networking
· Peripherals
· General Hardware
· Highly Technical
· Computer Help
· Home Theater PCs
· Consumer Electronics
· Digital and Video Cameras
· Mobile Devices & Gadgets
· Audio/Video & Home Theater
· Software
· Software for Windows
· All Things Apple
· *nix Software
· Operating Systems
· Programming
· PC Gaming
· Console Gaming
· Distributed Computing
· Security
· Social
· Off Topic
· Politics and News
· Discussion Club
· Love and Relationships
· The Garage
· Health and Fitness
· Merchandise and Shopping
· For Sale/Trade
· Hot Deals with Free Stuff/Contests
· Black Friday 2014
· Forum Issues
· Technical Forum Issues
· Personal Forum Issues
· Suggestion Box
· Moderator Resources
· Moderator Discussions
   

Reply
 
Thread Tools
Old 12-07-2008, 07:03 PM   #1
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

1993, 153k

The brake warning light is illuminated on the dash. I feels like maybe the rear brakes are sticking. The emergency brake will not hold vehicle on incline. Truck does not pull left or right.

10 or so years ago I replaced the front lines because they were collapsing. The truck would pull left or right that is why I suspect the rear brakes this time. The vehicle seems like it is dragging when I coast, pedal seems unresponsive for the first 25% when depressed. Once when I released the pedal at a stop sign I could feel the brakes slowly releasing as i moved forward, but they never fulling released. I never use the emergency brake, is there a cable that could be stuck?

Its dark here but I guess the first thing to do would be jack up truck and see which wheels seem to drag. Any other tips? thanks

previously posted in P&N and those guys were zero help
bctbct is offline   Reply With Quote
Old 12-07-2008, 07:28 PM   #2
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

Quote:
Originally posted by: bctbct
1993, 153k

The brake warning light is illuminated on the dash. I feels like maybe the rear brakes are sticking. The emergency brake will not hold vehicle on incline. Truck does not pull left or right.

10 or so years ago I replaced the front lines because they were collapsing. The truck would pull left or right that is why I suspect the rear brakes this time. The vehicle seems like it is dragging when I coast, pedal seems unresponsive for the first 25% when depressed. Once when I released the pedal at a stop sign I could feel the brakes slowly releasing as i moved forward, but they never fulling released. I never use the emergency brake, is there a cable that could be stuck?

Its dark here but I guess the first thing to do would be jack up truck and see which wheels seem to drag. Any other tips? thanks

previously posted in P&N and those guys were zero help
I think it's entirely possible on a truck of that age to have parking brake cables rusted up. But, you say you don't ever use it. Edit: You did use it. It probably didn't release fully and overheated the rear shoes. The light is on because it's not fully released. I'd pull the rears and have a look see. Look for signs of overheating. I'll leave the rest of this. Sorry I missed this point on the first read.

Raise the rear and see if one or both wheels are dragging.

The light will come on under three circumstances.

The parking brake is on, or not fully released.
There is an internal hydraulic failure in the Master Cylinder or an external hydraulic leak.
The brake fluid level is low in the Master Cylinder.
There is also the possibility of a short in that circuit, but, you are experiencing brake problems.

If you mash and hold the brake pedal, does it slowly sink to the floor? Does it seem to have more travel than normal? Do you feel you have less braking than you did prior?

Lastly, the self adjusters on the rear (I'm assuming they're drums) only adjust when the brake is applied in reverse. You can try making numerous stops in reverse to see if this improves the situation. I usually try to come to a full complete stop. Sometimes it takes the motion of the vehicle rocking forward to complete the self-adjust.

boomerang is online now   Reply With Quote
Old 12-07-2008, 07:44 PM   #3
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

Quote:
Originally posted by: boomerang
Quote:
Originally posted by: bctbct
1993, 153k

The brake warning light is illuminated on the dash. I feels like maybe the rear brakes are sticking. The emergency brake will not hold vehicle on incline. Truck does not pull left or right.

10 or so years ago I replaced the front lines because they were collapsing. The truck would pull left or right that is why I suspect the rear brakes this time. The vehicle seems like it is dragging when I coast, pedal seems unresponsive for the first 25% when depressed. Once when I released the pedal at a stop sign I could feel the brakes slowly releasing as i moved forward, but they never fulling released. I never use the emergency brake, is there a cable that could be stuck?

Its dark here but I guess the first thing to do would be jack up truck and see which wheels seem to drag. Any other tips? thanks

previously posted in P&N and those guys were zero help
I think it's entirely possible on a truck of that age to have parking brake cables rusted up. But, you say you don't ever use it.

Raise the rear and see if one or both wheels are dragging.

The light will come on under three circumstances.

The parking brake is on, or not fully released.
There is an internal hydraulic failure in the Master Cylinder or an external hydraulic leak.
The brake fluid level is low in the Master Cylinder.
There is also the possibility of a short in that circuit, but, you are experiencing brake problems.

If you mash and hold the brake pedal, does it slowly sink to the floor? Does it seem to have more travel than normal? Do you feel you have less braking than you did prior?

Lastly, the self adjusters on the rear (I'm assuming they're drums) only adjust when the brake is applied in reverse. You can try making numerous stops in reverse to see if this improves the situation. I usually try to come to a full complete stop. Sometimes it takes the motion of the vehicle rocking forward to complete the self-adjust.
When I mash the pedal it seems less reponsive the first 25%, although it does act normal after that and stop vehicle. It does not seem to lose pressure when I hold it down. I found no hydralic leaks.

I tried the reverse and brake to see if it was the self adjusters.

I drove it yesterday morning and there was no light, then last evening the light was on and syptoms present.

Given the slow release I felt through the pedal, maybe it is the MC.

edit

I only used the emergency brake to see if it was functioning thinking the truck was telling me the pads needed replaced. I dont recall doing the rears in the 14 yrs I have had the truck.



bctbct is offline   Reply With Quote
Old 12-07-2008, 07:54 PM   #4
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

Quote:
Originally posted by: bctbct
Quote:
Originally posted by: boomerang
Quote:
Originally posted by: bctbct
1993, 153k

The brake warning light is illuminated on the dash. I feels like maybe the rear brakes are sticking. The emergency brake will not hold vehicle on incline. Truck does not pull left or right.

10 or so years ago I replaced the front lines because they were collapsing. The truck would pull left or right that is why I suspect the rear brakes this time. The vehicle seems like it is dragging when I coast, pedal seems unresponsive for the first 25% when depressed. Once when I released the pedal at a stop sign I could feel the brakes slowly releasing as i moved forward, but they never fulling released. I never use the emergency brake, is there a cable that could be stuck?

Its dark here but I guess the first thing to do would be jack up truck and see which wheels seem to drag. Any other tips? thanks

previously posted in P&N and those guys were zero help
I think it's entirely possible on a truck of that age to have parking brake cables rusted up. But, you say you don't ever use it.

Raise the rear and see if one or both wheels are dragging.

The light will come on under three circumstances.

The parking brake is on, or not fully released.
There is an internal hydraulic failure in the Master Cylinder or an external hydraulic leak.
The brake fluid level is low in the Master Cylinder.
There is also the possibility of a short in that circuit, but, you are experiencing brake problems.

If you mash and hold the brake pedal, does it slowly sink to the floor? Does it seem to have more travel than normal? Do you feel you have less braking than you did prior?

Lastly, the self adjusters on the rear (I'm assuming they're drums) only adjust when the brake is applied in reverse. You can try making numerous stops in reverse to see if this improves the situation. I usually try to come to a full complete stop. Sometimes it takes the motion of the vehicle rocking forward to complete the self-adjust.
When I mash the pedal it seems less reponsive the first 25%, although it does act normal after that and stop vehicle. It does not seem to lose pressure when I hold it down. I found no hydralic leaks.

I tried the reverse and brake to see if it was the self adjusters.

I drove it yesterday morning and there was no light, then last evening the light was on and syptoms present.

Given the slow release I felt through the pedal, maybe it is the MC.

edit

I only used the emergency brake to see if it was functioning thinking the truck was telling me the pads needed replaced. I dont recall doing the rears in the 14 yrs I have had the truck.


I made an edit above but I really suspect the MS. Now, are their drums in the rear or disks? You said pads, so I'm not sure.

Also, the light was on before using the parking brake or after?
boomerang is online now   Reply With Quote
Old 12-07-2008, 08:04 PM   #5
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

Quote:
Originally posted by: boomerang



I made an edit above but I really suspect the MS. Now, are their drums in the rear or disks? You said pads, so I'm not sure.

Also, the light was on before using the parking brake or after?
[/quote]


Rear drums, I only used the parking brake after the light came on.
bctbct is offline   Reply With Quote
Old 12-07-2008, 08:14 PM   #6
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

If the fluid is not low, you've got a hydraulic leak. The light is on. You see no external leaks, so you have an internal leak.

Before I convicted the MS, if it were mine, I'd take a look at the rears. Pull the drums and have a look see. You say the parking brake will not hold on an incline. Look at the rears closely and correct any problems there before replacing the Master Cylinder.
boomerang is online now   Reply With Quote
Old 12-07-2008, 08:22 PM   #7
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

Quote:
Originally posted by: boomerang
If the fluid is not low, you've got a hydraulic leak. The light is on. You see no external leaks, so you have an internal leak.

Before I convicted the MS, if it were mine, I'd take a look at the rears. Pull the drums and have a look see. You say the parking brake will not hold on an incline. Look at the rears closely and correct any problems there before replacing the Master Cylinder.

will check the wheels tommorrow. thanks
bctbct is offline   Reply With Quote
Old 12-08-2008, 05:43 AM   #8
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

I was over-simplifying this last night. Here is what I think may be happening. There are two pistons in the Master Cylinder. One for the fronts and one for the rears. I think that the self-adjusters are frozen and the rear shoes are completely worn down. When you press the brake pedal, if there is a hydraulic failure, the piston will travel so far down the bore that it will make contact with a switch. This switch turns on the brake warning light.

In your case, the piston can't move enough fluid to actually apply the rears. In other words, the shoes move out, but they are so far away from the drums that there is not enough piston travel available to actually apply them. It travels far enough to trip the warning light. There is no hydraulic failure per se, but the switch is being tripped so it appears to be the case.

When you get the rear brakes working as they should, the first time you mash the pedal and the rear circuit builds up pressure, the switch for the warning light will be reset and the light will go out.

The braking power diminishes slowly over time so you don't really notice it.

They had a bad setup for a number of years with rear disks. The pistons would move out as the rear pads wore down as is normal. Eventually the pistons would reach the end of their travel and the rear brakes would slowly quit being effective. The parking brake needed to be applied to allow the pistons to travel further, but a whole lot of folks never ever use the parking brake with an automatic. People would sometimes drive for years with no rear brakes. The pedal would be firm because the rear pistons were mechanically stopped at the end of their travel. The rear pads would have a lot of material left on them, but the rotors would rust up something terrible.
boomerang is online now   Reply With Quote
Old 12-08-2008, 11:16 PM   #9
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

So far I found out that one of the rear brake shoes was broken. One of the rear brake lines has a minor leak. The other rear line has a compressed area, like the outside insulation has collapsed together creating an considerable overlaping.

Shoes still had 50% left but were not adjusted out to the drum so the self adjusters were probably frozen.

btw replacing the rears without spring pliers is a pain in the ass. will tackle the project tommorrow.
bctbct is offline   Reply With Quote
Old 12-09-2008, 06:06 PM   #10
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

Quote:
Originally posted by: bctbct
So far I found out that one of the rear brake shoes was broken. One of the rear brake lines has a minor leak. The other rear line has a compressed area, like the outside insulation has collapsed together creating an considerable overlaping.

Shoes still had 50% left but were not adjusted out to the drum so the self adjusters were probably frozen.

btw replacing the rears without spring pliers is a pain in the ass. will tackle the project tommorrow.
Sorry for your troubles, but I'm glad you found some real obvious problems. I'd pick up an inexpensive pair of pliers. You can really hurt youself trying to deal with those springs using makeshift methods.

I'd say that your Master Cylinder is fine. Looks like the problem is all in the rears.

Post back with your final results, I'd be interested to hear how it works out.
boomerang is online now   Reply With Quote
Old 12-15-2008, 06:47 PM   #11
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

update

dealer patched the brake line $125
dealer replaced rear cylinders because I had put a part in backwards when I replaced the shoes. When the brakes were under pressure it blew out a cylinder. Not sure what part could have done that...$225

it works, damn I hate car repair expenses!


bctbct is offline   Reply With Quote
Old 12-16-2008, 08:35 AM   #12
boomerang
Lifer
 
boomerang's Avatar
 
Join Date: Jun 2000
Location: Michigan
Posts: 13,614
Default Chevy truck brake problems

Quote:
Originally posted by: bctbct
update

dealer patched the brake line $125
dealer replaced rear cylinders because I had put a part in backwards when I replaced the shoes. When the brakes were under pressure it blew out a cylinder. Not sure what part could have done that...$225

it works, damn I hate car repair expenses!

What happens with rear wheel cylinders is that they corrode inside. When you put on new shoes, the pistons need to be pushed further into the cylinder. The seals ride over the corrosion and it tears them up. Usually on the first brake apply they start to leak. I learned this one the hard way a long, long time ago. The car made several stops but at the first red light the car sailed on through. Fortunately the light had just changed and there was no traffic in the intersection.

You used to be able to rebuild wheel cylinders. You could buy a rebuild kit and if they weren't corroded too bad, you could hone them and replace the seals and such. I can't imagine that in these days of expensive labor that it is cost effective to do so - if you can even buy the kits anymore.

This corrosion problem is in part why you hear people talk of getting their brake fluid flushed. Brake fluid attracts moisture. That moisture in the fluid causes corrosion over time. Flushing brake lines is a good thing, especially when you consider the cost of replacing an ABS unit.

Glad you got it going and thanks for reporting back your results. Sorry for the expense too.


boomerang is online now   Reply With Quote
Old 12-16-2008, 09:47 PM   #13
bctbct
Diamond Member
 
Join Date: Dec 2005
Posts: 4,868
Default Chevy truck brake problems

thanks for the help boomerang.
bctbct is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:09 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.