Brake pedal needs manually reset after depressing

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
New (rebuilt due to no one making new pumps with reservoirs) power steering pump seems to have resolved my issue. Added a new pulley while I had the pump out of the truck.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,038
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
New (rebuilt due to no one making new pumps with reservoirs) power steering pump seems to have resolved my issue. Added a new pulley while I had the pump out of the truck.
You can get a new pump and put your application specific reservoir on
 

Juggernaut

Full Access Member
Joined
Apr 11, 2021
Posts
203
Reaction score
215
Location
Illinois
First Name
Greg
Truck Year
78
Truck Model
K20
Engine Size
350
You said you bled the system, but it sounds like to me there's still air in it. I had the same symptoms you're having, and it took me several tries to get all the air out. Is there any foam in the fluid?
 

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
I did not see any foam in the system. Everything seemed to be working great initially but its back to doing the same thing again. I'll try to bleed it again and see if anything changes.
 
Last edited:

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
I have spent approximately 100 minutes turning the steering wheel lock to lock with the engine off since my last post. Each "lap" takes approximately 50 seconds due to me overfilling the system so that I can watch the fluid level from inside the cab. As such, I have completed well over 100 laps and am still getting bubbles on almost every revolution. I have rechecked my connections and they all seem to be tight. I am going to apply vacuum to the reservoir to see if it holds, I have a strong suspicion that I have a leak somewhere. Plan is to undo each connection, starting with the highest one, disconnect/reconnect and recheck with vacuum pump.

-Eric
 
Last edited:

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,038
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
I have spent approximately 100 minutes turning the steering wheel lock to lock with the engine off since my last post. Each "lap" takes approximately 50 seconds due to me overfilling the system so that I can watch the fluid level from inside the cab. As such, I have completed well over 100 laps and am still getting bubbles on almost every revolution. I have rechecked my connections and they all seem to be tight. I am going to apply vacuum to the reservoir to see if it holds, I have a strong suspicion that I have a leak somewhere. Plan is to undo each connection, starting with the highest one, disconnect/reconnect and recheck with vacuum pump.

-Eric
Could the pump not be sealed properly and it’s introducing air each revolution
 

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
Quite possible. If the vacuum pump diagnostic strategy doesn’t lead me to a potential leak, I plan to use a tracer dye and UV light.

Missing out on the limited nice weather days here in PA...
 
Last edited:

Juggernaut

Full Access Member
Joined
Apr 11, 2021
Posts
203
Reaction score
215
Location
Illinois
First Name
Greg
Truck Year
78
Truck Model
K20
Engine Size
350
Look for fluid leaks anywhere in the system, if fluid can get out, air can get in. You shouldn't need to take apart anything that's not leaking. Try this, raise the front of the truck, wheels off the ground. Start the engine and run it up to about 1500 rpm. Keep it at 1500 and turn the wheel lock to lock. Check the reservoir and add fluid if needed. Do this till the fluid level stays the same. Then lower the truck. Leave the engine running and turn from lock to lock while also pushing the brake pedal in and out several times. Turn the engine off, and push the brake pedal 4 or 5 more times. Check the fluid level, if it's low, add fluid and do this all again. It took me 3 or 4 tries doing this, but it finally got all the air out. Hope this helps!
 

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
-put yellow teflon tape on all of the flare fittings and confirmed they are tight, not cross threaded and not leaking.

-replaced both rubber return lines. That is the PS pump to Hydroboost and PS pump lines. I already replace both pressure hoses.

-replaced all of the hose clamps in the system and ensured they were tight

-bled the air in the normal, wheels elevated, lock to lock multiple times fashion

-used a vacuum pump at 15mmHg which held vacuum confirming that there are no leaks

-turned the wheels lock to lock 10 additional times without seeing a single bubble

Pedal returns much more frequently, steering and braking have are quieter but the pedal still hangs occasionally. It most frequently occurred when I applied slight pressure when slowing. From a stop, I found that the pedal resets once I’ve begun to accelerate.

Going to continue trying to bleed more air from the system with the vacuum pump. Also going to spend the 5 or so bucks to replace the pedal return spring.

Earlier in this thread, @AKguy mentioned that hydroboost units possibly had different rods of different lengths... the one I installed is 71217. Like an idiot, I didn’t measure or note the stamping on the rod that came off the truck before I tossed it.

Does anyone know the other stamping number and/or length? Truth be told, I don’t even know the length of the rod on the unit installed in my truck.

@Rusty Nail, I added pic for you!

-Eric

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
 
Last edited:

Juggernaut

Full Access Member
Joined
Apr 11, 2021
Posts
203
Reaction score
215
Location
Illinois
First Name
Greg
Truck Year
78
Truck Model
K20
Engine Size
350
I think you have taken care of any air issues you had, if the squealing has gone away and no more bubbles. Is your brake pedal real loose, sloppy?
 

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
There is a low hum when I hold the pedal depressed but it is nothing like the groaning I had before.

As far as the pedal being sloppy, the brake pedal has maybe 1/8” of play side to side and maybe 1/4” forward and back/up and down before it starts meeting resistance.

-Eric
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,038
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Sounds like it’s binding or it goes far enough that the angle of the pedal spring doesn’t yank the pedal out. I Would look at spring pivots locations lf stuff, check the ram thingy for straightness c, check the pedal arm for straightness and shiny sides.irrc does the pedal ride up close to part of the bracket on a bushing , so of it pushed just right it could be friction hold or something idk
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,038
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
This may seem stupid simple but do you have hydro pedals? Is it a swap? Not sure if that could affect it. But looking at the pedals the bushin the pedal is on could be worn or the bracket could be squeezed in slightly and it allows the pedal to get caught some how
 

84K30

Full Access Member
Joined
Jul 14, 2019
Posts
156
Reaction score
64
Location
SWPA
First Name
Eric
Truck Year
1984
Truck Model
K30
Engine Size
454
Factory hydroboost. This pedal issue only began after I replaced a the hydroboost unit due to it leaking all over everything.

Eric
 
Last edited:

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,038
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Factory hydroboost. This pedal issue began after I replaced a the hydroboost unit due to it leaking all over everything.

Eric
Is the hydro boost maybe have internal manufacturing defect where the bore is not smooth or something can catch. Idk how it works but adjustments and hb unit are about all that’s left to be
 

Latest posts

Forum statistics

Threads
41,857
Posts
903,629
Members
33,370
Latest member
mitchell1128
Top