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Aloha! My 1990 C-1500 454 SS rear brakes locked up and severely overheated. I did a recent 4-wheel overhaul; new wheel cylinders, hardware, shoes and drums. I did not replace the master and bleeding t
Aloha! My 1990 C-1500 454 SS rear brakes locked up and severely overheated. I did a recent 4-wheel overhaul; new wheel cylinders hardware, shoes and drums (new rotors, calipers, pads, hose). I did not replace the master cylinder and bleeding the system wasn't problematic. Thought the dashboard brake indicator light came on because of front disc brake wear--disconnected the battery to turn the light off. The brake system was working well with heavy use several months ago, the truck was hardly driven since and was only driven 4 miles when the problem occurred. Any suggestions as to what's malfunctioning? Mahalo nui loa...
Re: Aloha! My 1990 C-1500 454 SS rear brakes locked up...
Check the flexible brake hose on the rear brakes , they some times brake down and stop the fluid from returning, if ok open a bleeder screw , if fluid is expelled and the wheels are free to turn replace the master cylinder
Re: Aloha! My 1990 C-1500 454 SS rear brakes locked up...
Is ther a rear brake equaliser on the rear axle? this is usually spring operated that pulls up on the rear brake limiter depending on load in vehicle may be stuck in the vehicle loaded position when the vehicle isnt carrying much weight worth a look , just jack up rear end and look for spring device centre of rear axle attached to a device with the brake lines entering/exiting if there get vehicle as high as safe to do then put blocks under rear wheels then slowly lower jack and look to see if the spring device moves down with the vehicle if not this could be the problem as is exerting pressure to rear brakes so causing them to over heat keep me posted
Testimonial: "Aloha and mahalo! There is no spring-actuated equilizer device as you described--only a one-into-two hydraulic brake line fitting. The brake lines look fine--no kinks or other damage. Removed the wheels and the drums still seemed locked up; they easily became free with a few taps of a hammer. The brake components were slightly burned but not destroyed--like how the rear brakes might look after going racing and doing (at least) several two-gear burnouts. The wheel cylinders seem to look okay...The brakes locked up on the road after a short 4 mile drive and the parking/E brake was never actuated; after the lock-up occurred, I tested the parking brake and there was slack, indicating the rear brakes were still locked.
The lock-up appears to be a hydraulic system problem. The dash brake light was on--even throwing a 'code 9' before I overhauled the entire system--I thought it appeared because the discs, calipers, pads and lines were at the end of their service life. I haven't checked and/or fired the engine to see it the light's back on because of the lock-up...
I'm now thinking master cylinder (didn't replace it because it seemed to be functioning well and all four corners of the brake system bled smoothly), dump valve or the ABS. I thought that if the ABS failed, it doesn't cause a lock-up condition. The fronts--with all new calipers, pads, rotors, bearings, etc. seem to be functioning well. There's still a good, firm feeling on the brake pedal, although the pedal travel was slightly more when the rears locked up. I've serviced the brake system before (even after torturing 'em drag racing) with no problems...I don't have my factory repair manuals here with me; mahalo nui/thank you very much for all your help! ---Bryan"
are the return springs fitted ok/still where you fitted them as if the brake are applied and the return spring isnt returning the leading shoe wont be long before the heat build up will caus ethe lining to fuse to the drum , worth a checkare the return springs fitted ok/still where you fitted them as if the brake are applied and the return spring isnt returning the leading shoe wont be long before the heat build up will caus ethe lining to fuse to the drum , worth a check
Aloha Steve--The return springs are correct--I disassembled both rears, cleaned the parts, relubed the backing plate, reassembled and adjusted. I did one side at a time and didn't have to bleed the rear brakes. They adjusted nearly as well as before the lock-up problem. It still feels like the brakes are dragging and it gets worse if I apply the parking brake and step on/pump the foot brake; the 454's torque can't move the truck normally at idle (and it really is acting like a roll/control line-lock, only on the rear brakes). The in-dash parking/e- brake light's on now and gets brighter when the p/e brake is applied; I'm now thinking proportioning valve, dump valve, ABS or even the master cyl.. I have no way of scanning the brake system and the front brakes afre functioniong well...Aloha Steve--The return springs are correct--I disassembled both rears, cleaned the parts, relubed the backing plate, reassembled and adjusted. I did one side at a time and didn't have to bleed the rear brakes. They adjusted nearly as well as before the lock-up problem. It still feels like the brakes are dragging and it gets worse if I apply the parking brake and step on/pump the foot brake; the 454's torque can't move the truck normally at idle (and it really is acting like a roll/control line-lock, only on the rear brakes). The in-dash parking/e- brake light's on now and gets brighter when the p/e brake is applied; I'm now thinking proportioning valve, dump valve, ABS or even the master cyl.. I have no way of scanning the brake system and the front brakes afre functioniong well...
could be the abs distribution control box , putting more pressure to the rear and not releasing after foot pedal released , cars can send you mad but what's the alternative other than a good woman ,good luck and keep me postedcould be the abs distribution control box , putting more pressure to the rear and not releasing after foot pedal released , cars can send you mad but what's the alternative other than a good woman ,good luck and keep me posted
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Your description sounds like the brakes are WAY out of adjustment. The brake cylinders need the shoes to hit the drum or they will do exactly what you describe. I always adjust the shoes until they lock the wheel, then back off until the wheel spins freely, usually 8 to 20 clicks.
Buy new wheel lock cylinders remove the brake drum then the shoes and spring follow be the brake line then you can remove the cylinder and replace in remember that you must bleed the brake line after doing this start with the farthest from the master cyclinder also good time to replace shoe spings and hardware since you will have to adjust the rear brakes any ways
After you remove the tire, the drim should slide off. If it doesn't then try using a rubber mallet and gently tap on the outside edge as you pull on it. Sometimes you also need to tap on the drum in the center part. I have sprayed penetrating lubes like WD-40 or PB Blaster into the seam at the center. You may also have to back off the parking brake cable or even use the adjuster to back off the shoes.
Do you have drum or disc rear brakes? If drum, the wheel cylinder probably needs to be replaced. If the wheel has overheated at any time, you should also replace the hardware (springs, etc) as they can lose their ability to retract the shoes if overheated. If disc brakes on rear, then the caliper is probably to blame. Has the brake fluid ever been changed? Fluid absorbs moisture (never use brake fluid from an open or not tightly sealed container). After rebuilding or replacing the caliper or wheel cyl. bleed all 4 wheels to flush out old fluid, otherwise you may have other wheels w/ brakes dragging/not releasing. Let me know if this doesn't fix it, I'll help further.
Your problem would appear to be something amiss in the rear brake on the locked wheel. If a wheel sylinder was leaking the brake shoes would become "sticky" and cause the shoes to "lock on" to the drum. Or if the brake was out of adjustment, the assembly could come apart and pieces of it jamb the wheel. This problem is fairly common with drum brakes. You need to have the rear brakes serviced, & checked for fluid or grease on the braking surfaces. All leaks fixed, backing plates cleaned, the wheel cylinders overhauled, & the brake shoes replaced.
Does it lock when cold (when 1st driven for the day) or after driving for a while? Pull off the wheel and drum and check for evidence of brake fluid (a leaking brake cylinder) or grease (a bad axle grease seal), either of these can cause the brakes to 'grab' or lock up. If this is what you find, you need to correct the leak problem and replace the brake shoes, which have become contaminated with the fluid. You should always change both rear or front brakes together for the best performance. Also check to make sure the springs and other hardware have not broken or become detached from their mounting positions. After driving for a while, carefully touch the wheel where the lug nuts are to see if that wheel is hotter to touch than the others. If it is, the brakes are 'dragging', not releasing completely as you drive, and heating up. This will also cause them to 'grab' or lock up. If this is the case, back off on the adjuster to see if that solves the problem, but more likely, it is a bad brake cylinder (corrosion inside the brake cylinder) which is causing it to hang up, and not release when you take your foot off the brake. If this is the problem, replace the brake cylinder at the rear wheel, and flush out the brake lines to avoid a similar problem in the near future with the other wheels. If the wheel was overheating due to the problem, you also need to replace the brake hardware(springs do not work properly when severely overheated).
HI THERE
YOU PROBLEM IS YOU NEED TO REPLACE THE PARKING BRAKE CABLES .THEY ARE RELEASED BUT NOT ALL THE WAY CAUSING THE SHOES TO SIT TO CLOSE TO THE DRUMS.WHEN ADJUSTING YOUR BRAKES HAVE THE REAR END OF THE TRUCK OFF THE GROUND TIRES ON AND SLOWLY ADJUST ADJUSTERS AT THE SAME TIME TURNING THE TIRE UNTIL YOU FEEL A SLIGHT DRAG REPEAT FOR OTHER WHEEL
Drum, Rear Brake System
Standard Rear Brake
Item
Part Number
Description
1
2069
Brake Shoe Hold-Down Spring Pin
2
—
Rear Wheel Cylinder Retaining Bolt (2 Req'd)
3
—
Washer (2 Req'd)
4
—
Anchor Pin (Part of 2211)
5
—
Wheel Cylinder
6
2028
Brake Shoe Anchor Pin Guide Plate
7
2A637
Parking Brake Lever
8
2296
Brake Shoe Retracting Spring (Short)
9
2296
Brake Shoe Retracting Spring (Long)
10
2200
Rear Brake Shoe and Lining (Secondary)
11
—
Washer
12
2106
Parking Brake Lever Pin Retainer
13
—
Brake Shoe Adjusting Lever Cable Guide
14
2A642
Primary Brake Shoe Parking Brake Lever Link
15
2A601
Parking Brake Link Spring
16
2068
Brake Shoe Hold-Down Spring
17
2A176
Brake Shoe Adjusting Lever
18
2048
Brake Shoe Adjusting Screw Socket
19
2047
Brake Shoe Adjusting Screw Nut
20
2041
Brake Adjusting Screw
21
2049
Brake Shoe Adjusting Screw Spring
22
2200
Rear Brake Shoe and Lining (Primary)
23
2A178
Brake Shoe Adjusting Lever Cable
24
2211
Brake Backing Plate
Heavy Duty Rear Brake
Item
Part Number
Description
1
—
Rear Wheel Cylinder Retaining Bolt
2
00538
Lock Nut
3
2212
Rear Brake Backing Plate
4
2262
Rear Wheel Cylinder
5
2A642
Primary Brake Shoe Parking Brake Lever Link
6
2A601
Parking Brake Link Spring
7
2A637
Parking Brake Lever
8
2106
Parking Brake Lever Pin Retainer
9
—
Parking Brake Lever Bolt
10
—
Secondary Shoe Assembly
11
2A179
Brake Shoe Adjusting Lever Cable Guide
12
2068
Brake Shoe Hold-Down Spring
13
—
Adjusting Lever Pin
14
—
Adjusting Lever Return Spring
15
2A176
Brake Shoe Adjusting Lever
16
2047
Brake Shoe Adjusting Screw Nut
17
2049
Brake Shoe Adjusting Screw Spring
18
2041
Brake Adjuster Screw
19
—
Primary Shoe Assembly
20
2068
Brake Shoe Hold-Down Spring
21
2200
Rear Brake Shoe and Lining
22
2035
Brake Shoe Retracting Spring
23
2A178
Brake Shoe Adjusting Lever Cable
24
2092
Brake Adjusting Hole Cover
25
2069
Brake Shoe Hold-Down Spring Pin
The rear drum brakes:
Have internal shoes that expand against the brake drum (1126).
Are a single-anchor type.
Are actuated by one rear wheel cylinder (2262).
Have two pistons in the rear wheel cylinder (2261). One exerts force against the upper end of the primary shoe; the other exerts force against the upper end of the secondary shoe.
Adjust rear brake shoes and linings (2200) automatically.
Need manual brake adjustment if the adjusters are not operating properly or after the rear brake shoes and linings have been replaced.
When the brake pedal is applied, hydraulic fluid pressure forces the pistons in the rear wheel cylinder outward, moving the rear brake shoes and linings against the brake drum.
The rear drum brake system includes the parking brake mechanism. Refer to Section 206-05 .
i think your aware of how to change the brakes if im right and your problem is the rusted drum doesnt want to come off the only way to get the old drum off is to remove adjuster plug from behind drum dustshield and adjust the shoes so that there not even close to the braking area of the drum then try and wiggle the drum off of the assembly if it is not coming off then you need to use the old nylon hammer on the drum and i mean you must hit the drum from side to side trying by hand to wiggle the drum off its a tight fit and you need to strike the drum on the face not on the fins not wanting to damage with persistance and care and patience you will eventually be able to remove the drum to service brakes take care and good luck with it
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