Hydro boost help
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
Likes: 11
From: Boiling Springs
Hydro boost help
So I’m having a bit of an issue finishing up my hydroboost. For some reason I can seem to get it to lock up the front wheels or ever get the braking power I was expecting. I’d drive around and try and lock up the wheels and I just couldn’t get it to.
here is what I have:
I have the stock proportioning valve in it
I got a brand new wilwood tandem model 260-8556
i have the d8-6 and d8-4 calipers on it
i got a hydroboost out of an Astro and I’m getting 13/16 extension with the pedal extended
i have another proportioning valve on the tandem master
i called willwood and the guy seems to think that my stock proportioning valve might be the reason. Went to the Bette show and talked to the wilwood rep and he said it’s the fact him not getting an inch of extension from the booster and I should go manual brakes. I don’t have much of a gap between the master and the tandem, so I think I finally got that fixed. Is their more I need to do with the pedal? Adjust it more? Or is the hydroboost just not giving me enough Tavel?
here is what I have:
I have the stock proportioning valve in it
I got a brand new wilwood tandem model 260-8556
i have the d8-6 and d8-4 calipers on it
i got a hydroboost out of an Astro and I’m getting 13/16 extension with the pedal extended
i have another proportioning valve on the tandem master
i called willwood and the guy seems to think that my stock proportioning valve might be the reason. Went to the Bette show and talked to the wilwood rep and he said it’s the fact him not getting an inch of extension from the booster and I should go manual brakes. I don’t have much of a gap between the master and the tandem, so I think I finally got that fixed. Is their more I need to do with the pedal? Adjust it more? Or is the hydroboost just not giving me enough Tavel?
Burning Brakes
Joined: Apr 2002
Posts: 1,105
Likes: 114
From: Lawrenceburg, KY
General advice/input only:
- If you have changed your calipers and master cylinder to non-factory (piston sizes/bore), then the proportioning valve must also change. The factory proportioning valve is designed to work with the factory setup, so when you change anything (away from the factory specs), then the factory proportioning is not longer relevant.
Replace the stock proportioning valve with adjustable propositioning valve.
- If you have changed your calipers and master cylinder to non-factory (piston sizes/bore), then the proportioning valve must also change. The factory proportioning valve is designed to work with the factory setup, so when you change anything (away from the factory specs), then the factory proportioning is not longer relevant.
Replace the stock proportioning valve with adjustable propositioning valve.
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
So I’m having a bit of an issue finishing up my hydroboost. For some reason I can seem to get it to lock up the front wheels or ever get the braking power I was expecting. I’d drive around and try and lock up the wheels and I just couldn’t get it to.
here is what I have:
I have the stock proportioning valve in it
I got a brand new wilwood tandem model 260-8556
i have the d8-6 and d8-4 calipers on it
i got a hydroboost out of an Astro and I’m getting 13/16 extension with the pedal extended
i have another proportioning valve on the tandem master
i called willwood and the guy seems to think that my stock proportioning valve might be the reason. Went to the Bette show and talked to the wilwood rep and he said it’s the fact him not getting an inch of extension from the booster and I should go manual brakes. I don’t have much of a gap between the master and the tandem, so I think I finally got that fixed. Is their more I need to do with the pedal? Adjust it more? Or is the hydroboost just not giving me enough Tavel?
here is what I have:
I have the stock proportioning valve in it
I got a brand new wilwood tandem model 260-8556
i have the d8-6 and d8-4 calipers on it
i got a hydroboost out of an Astro and I’m getting 13/16 extension with the pedal extended
i have another proportioning valve on the tandem master
i called willwood and the guy seems to think that my stock proportioning valve might be the reason. Went to the Bette show and talked to the wilwood rep and he said it’s the fact him not getting an inch of extension from the booster and I should go manual brakes. I don’t have much of a gap between the master and the tandem, so I think I finally got that fixed. Is their more I need to do with the pedal? Adjust it more? Or is the hydroboost just not giving me enough Tavel?
I have the same setup but using the factory vacuum power booster. Too lockup the front brakes you need great brake pads / no air in the brake system. With wilwood calipers in the rear it is difficult to bleed properly. You will need to stand the calipers vertical and bleed off the car.
You will also need to bleed the MC While on the car. Like this
Get the last bit of air out from the brake master cylinder. - CorvetteForum - Chevrolet Corvette Forum Discussion
Once this is clear of air, Then bleed the rear calipers off the car, then bleed the front.
you dont need to change anything since the MC / Calipers are the same as factory specs. If you have sticky front 18" wheels you will need high friction pads to lock up.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
Likes: 11
From: Boiling Springs
I setup the MC / brake booster a little pre-loaded (no clearance) for faster brake response.
I have the same setup but using the factory vacuum power booster. Too lockup the front brakes you need great brake pads / no air in the brake system. With wilwood calipers in the rear it is difficult to bleed properly. You will need to stand the calipers vertical and bleed off the car.
You will also need to bleed the MC While on the car. Like this
Get the last bit of air out from the brake master cylinder. - CorvetteForum - Chevrolet Corvette Forum Discussion
Once this is clear of air, Then bleed the rear calipers off the car, then bleed the front.
you dont need to change anything since the MC / Calipers are the same as factory specs. If you have sticky front 18" wheels you will need high friction pads to lock up.
I have the same setup but using the factory vacuum power booster. Too lockup the front brakes you need great brake pads / no air in the brake system. With wilwood calipers in the rear it is difficult to bleed properly. You will need to stand the calipers vertical and bleed off the car.
You will also need to bleed the MC While on the car. Like this
Get the last bit of air out from the brake master cylinder. - CorvetteForum - Chevrolet Corvette Forum Discussion
Once this is clear of air, Then bleed the rear calipers off the car, then bleed the front.
you dont need to change anything since the MC / Calipers are the same as factory specs. If you have sticky front 18" wheels you will need high friction pads to lock up.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
Likes: 11
From: Boiling Springs
General advice/input only:
- If you have changed your calipers and master cylinder to non-factory (piston sizes/bore), then the proportioning valve must also change. The factory proportioning valve is designed to work with the factory setup, so when you change anything (away from the factory specs), then the factory proportioning is not longer relevant.
Replace the stock proportioning valve with adjustable propositioning valve.
- If you have changed your calipers and master cylinder to non-factory (piston sizes/bore), then the proportioning valve must also change. The factory proportioning valve is designed to work with the factory setup, so when you change anything (away from the factory specs), then the factory proportioning is not longer relevant.
Replace the stock proportioning valve with adjustable propositioning valve.
Burning Brakes
Joined: Apr 2002
Posts: 1,105
Likes: 114
From: Lawrenceburg, KY
I run adjustable proportioning valves on anything I hot rod/mod (provided it doesn't have ABS). If you install an adjustable valve, set the rear almost off, and still can't lock the front then you need more pad at the front (or have a really bad mismatch of master and caliper sizes).
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
I bleed the MC first, then pressure bleed the calipers.
so when installing a new MC, blench bleed first, install in the vehicle, fill the calipers using pressure bleeding, once the system is full, bleed the MC while on the car, and finally re-bleed each caliper.
