Go Back   GM Square Body - 1973 - 1987 GM Truck Forum > '73 - '87 GM Truck Modifications > Suspension, Steering & Brakes
Become a Supporting Member         Become a Preferred Vendor

Advertisements

Suspension, Steering & Brakes Brake Repair, Disc Brake Conversions, Suspension Replacement, Steering & Alignment


User Tag List

Reply
 
Thread Tools Display Modes
Old 03-20-2017, 03:07 PM   #1
 
76chevyc20454's Avatar
76chevyc20454
Member
 
Join Date: Apr 2015
Location: Indiana
Name: Justin
Posts: 61

Year: 1976
Model: c20
Engine: 454

Rep Power: 8

76chevyc20454 is on a distinguished road
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Default Brake problem
I have a 76k10 and sometimes when i go to brake the pedal goes fo the floor and the passenger side wheel will lock up.

76chevyc20454 is offline   Reply With Quote
Old 03-20-2017, 03:11 PM   #2
 
da_raabi's Avatar
da_raabi
Senior Member
 
Join Date: Aug 2013
Location: Somewhere hot...
Name: Adam
Age: 28
Posts: 694

Year: 1986
Model: c30
Engine: 454

Rep Power: 30

da_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to behold
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Default
Hmm thats interesting. Brake to the floor makes me think master cylinder or a blown line, but the locked wheel makes me thing either stuck caliper or collapsed hose. How old are all your brake components? Are the hoses ancient? When you say pass wheel, do you mean front or back? If back, are they drums?

Need info!


__________________
1980 Camaro INTERCEPTOR
1986 Chevy C30 Crew Cab "Big Dooley"

REAL TRUCKS DONT DRAG THEIR ASS! LIFT IT RIGHT! http://i268.photobucket.com/albums/j...psfpxtuozz.jpg

Hold my beer... I've got an idea!
You know, when I see a Prius I laugh and think about how many it would take to make up for MY gas mileage... EAT MY CARBON TOYOTA!!!
da_raabi is offline   Reply With Quote
Old 03-20-2017, 03:19 PM   #3
 
76chevyc20454's Avatar
76chevyc20454
Member
 
Join Date: Apr 2015
Location: Indiana
Name: Justin
Posts: 61

Year: 1976
Model: c20
Engine: 454

Rep Power: 8

76chevyc20454 is on a distinguished road
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Default
Originally Posted by da_raabi View Post
Hmm thats interesting. Brake to the floor makes me think master cylinder or a blown line, but the locked wheel makes me thing either stuck caliper or collapsed hose. How old are all your brake components? Are the hoses ancient? When you say pass wheel, do you mean front or back? If back, are they drums?

Need info!
Front passenger wheel and i just bought the truck so not sure how old it is
76chevyc20454 is offline   Reply With Quote
Old 03-20-2017, 03:35 PM   #4
 
CSFJ's Avatar
CSFJ
Senior Member
 
Join Date: Jul 2014
Location: Michigan
Name: Christian
Age: 41
Posts: 1,432

Year: 1984, 1987
Model: D30, V20
Engine: 6.2ltr, 350

Rep Power: 22

CSFJ is a jewel in the roughCSFJ is a jewel in the roughCSFJ is a jewel in the rough
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Default
Is the brake resevoir full? Do any puddles of fluid form if you press the brake pedal in while parked?
CSFJ is offline   Reply With Quote
Old 03-20-2017, 08:32 PM   #5
 
76chevyc20454's Avatar
76chevyc20454
Member
 
Join Date: Apr 2015
Location: Indiana
Name: Justin
Posts: 61

Year: 1976
Model: c20
Engine: 454

Rep Power: 8

76chevyc20454 is on a distinguished road
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Default
No puddles on the ground but i notice its slowling leaking out the cap of the master cylinder.
76chevyc20454 is offline   Reply With Quote
Old 03-21-2017, 08:27 AM   #6
 
da_raabi's Avatar
da_raabi
Senior Member
 
Join Date: Aug 2013
Location: Somewhere hot...
Name: Adam
Age: 28
Posts: 694

Year: 1986
Model: c30
Engine: 454

Rep Power: 30

da_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to beholdda_raabi is a splendid one to behold
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Default
If it were me I'd do the following:

1. Replace the calipers if they look original
2. Replace the brake hoses too
3. Since they are cheap, replace the master cylinder
4. Flush the system with new fluid and bleed, bleed, bleed

The only other component that could go wrong at that point is the prop valve, which is unlikely considering your issue is isolated to one wheel

Having good brakes is the most important part of your truck, so for under $100 you can have known-good brakes, at least up front (drums are another story) that you can rely on.

Before you spend any real money, you can try flushing out the old brake fluid and see if that improves anything, but be prepared to spend some money. I'm guessing you either have a collapsed hose or a bad M/C but see what happens with a good flush.


__________________
1980 Camaro INTERCEPTOR
1986 Chevy C30 Crew Cab "Big Dooley"

REAL TRUCKS DONT DRAG THEIR ASS! LIFT IT RIGHT! http://i268.photobucket.com/albums/j...psfpxtuozz.jpg

Hold my beer... I've got an idea!
You know, when I see a Prius I laugh and think about how many it would take to make up for MY gas mileage... EAT MY CARBON TOYOTA!!!
da_raabi is offline   Reply With Quote
Old 03-21-2017, 03:00 PM   #7
 
chengny's Avatar
chengny
Senior Member
 
Join Date: Feb 2012
Location: NH
Name: Jerry
Age: 58
Posts: 3,120

Year: 1986
Model: K3500
Engine: 350/5.7

Rep Power: 95

chengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond reputechengny has a reputation beyond repute
Mentioned: 64 Post(s)
Tagged: 3 Thread(s)
Default
Put me down for the MC is shot.

Brake fluid can only leak out of the system - it can't leak in. So if there is brake fluid leaking out of the MC cap, it must be migrating from one hydraulic circuit to the other (i.e. front to back or vise-versa). I bet if you pull the cap and check, one reservoir will be full to the rim and the other will be down.
chengny is offline   Reply With Quote
Old 03-21-2017, 09:45 PM   #8
 
Georgeb's Avatar
Georgeb
Senior Member
 
Join Date: Apr 2015
Location: Wisconsin
Name: George
Age: 37
Posts: 2,920

Year: 2003
Model: K10 Burb Z71
Engine: 5.3

Rep Power: 32

Georgeb is a splendid one to beholdGeorgeb is a splendid one to beholdGeorgeb is a splendid one to beholdGeorgeb is a splendid one to beholdGeorgeb is a splendid one to beholdGeorgeb is a splendid one to behold
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Default
Originally Posted by chengny View Post
Put me down for the MC is shot.

Brake fluid can only leak out of the system - it can't leak in. So if there is brake fluid leaking out of the MC cap, it must be migrating from one hydraulic circuit to the other (i.e. front to back or vise-versa). I bet if you pull the cap and check, one reservoir will be full to the rim and the other will be down.
I'm with this guy.
Georgeb is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hard brake pedal, loss of brake fluid, new (to me) 79 k10 TheBlueBomber Brakes 8 07-17-2013 07:17 PM
Mushy Brake Problem fowjacob Brakes 17 06-11-2013 04:13 PM
Brake Light Problem GOBR Electrical & Audio 12 05-01-2013 07:42 AM
brake light speedo problem timbo350 Tech Discussion 2 04-07-2013 09:44 AM
my brake bleeding problem, on a gmt400 tho. Swims350 Brakes 37 09-16-2012 10:15 AM