Power Booster Install - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mshirey · 06-18-2010, 10:24 PM

I'm converting from manual drum brakes to power drum brakes and the brake pedal seems lower than I expected. For those that have done this conversion, I'm wondering how much lower your pedal was after the change. I have the min 3/4" thread depth in the clevis but that leaves the pedal quite a bit lower then the clutch pedal. I was expecting it be lower but not sure how much lower it should be.

How much lower was your brake pedal after the conversion?

Thanks,

-mike

Shyguy · 06-19-2010, 10:06 AM

Is the peddle lower with the engine running?

When my son puts on brake boosters he has to change the length of the push rod I think.

Sorry I could not be more help since I have never done it myself.

Danny

oldblue1968chevy · 06-19-2010, 11:07 AM

your rod going to your brake pedel is out of adj.

69pickupnyc · 06-19-2010, 12:52 PM

I just did the install and the problem that I was having was with the length of the rod. The rod should be at a length that you do not have to touch the brake peddle to get the connecting rod to go in. The next problem you may have if the brake peddle does not extend all the way back thus fully releasing the brake fluid pressure. This may happen if you removed the plate underneath the steering wheel on the bottom of the dash board to attach the brake rod from the power boster. When the plate is reinstalled it can push the BRAKE PEDDLE foward thus the brake fluid pressure is not fully released. If you do not fully release the pressure afterafter stepping on the brake peddle several times your brakes may lock up. It also seems to me that your brakes are not adjusted properly. JOE 1-718-634-1268

mshirey · 06-21-2010, 02:15 AM

Thanks for the comments and suggestions. I agree the rod length is not quite right. Installation instructions state to keep a minimum 3/4" of push rod thread in the clevis and that lower pedal is normal. I'm at 3/4" now. I'm going to double check this to make sure I'm at 3/4".

The pedal is not hitting the return stop pad now so I should not have any issues with brake drag.

I might have to consider modification to the push rod for additional length. Probably will wait until after engine swap is complete and I can test performance without modification.

06-18-2010, 10:24 PM	#1
mshirey Registered User Join Date: Apr 2000 Location: San Diego, CA Posts: 110	Power Booster Install I'm converting from manual drum brakes to power drum brakes and the brake pedal seems lower than I expected. For those that have done this conversion, I'm wondering how much lower your pedal was after the change. I have the min 3/4" thread depth in the clevis but that leaves the pedal quite a bit lower then the clutch pedal. I was expecting it be lower but not sure how much lower it should be. How much lower was your brake pedal after the conversion? Thanks, -mike __________________ Mike 67' GMC Fleetside

06-19-2010, 10:06 AM	#2
Shyguy Junior Member Join Date: Dec 2006 Location: Southeast Missouri Posts: 2,436	Re: Power Booster Install Is the peddle lower with the engine running? When my son puts on brake boosters he has to change the length of the push rod I think. Sorry I could not be more help since I have never done it myself. Danny __________________ '67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E.

06-19-2010, 11:07 AM	#3
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Power Booster Install your rod going to your brake pedel is out of adj. __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

06-19-2010, 12:52 PM	#4
69pickupnyc Registered User Join Date: Dec 2009 Location: new york city new york Posts: 32	Re: Power Booster Install I just did the install and the problem that I was having was with the length of the rod. The rod should be at a length that you do not have to touch the brake peddle to get the connecting rod to go in. The next problem you may have if the brake peddle does not extend all the way back thus fully releasing the brake fluid pressure. This may happen if you removed the plate underneath the steering wheel on the bottom of the dash board to attach the brake rod from the power boster. When the plate is reinstalled it can push the BRAKE PEDDLE foward thus the brake fluid pressure is not fully released. If you do not fully release the pressure afterafter stepping on the brake peddle several times your brakes may lock up. It also seems to me that your brakes are not adjusted properly. JOE 1-718-634-1268

06-21-2010, 02:15 AM	#5
mshirey Registered User Join Date: Apr 2000 Location: San Diego, CA Posts: 110	Re: Power Booster Install Thanks for the comments and suggestions. I agree the rod length is not quite right. Installation instructions state to keep a minimum 3/4" of push rod thread in the clevis and that lower pedal is normal. I'm at 3/4" now. I'm going to double check this to make sure I'm at 3/4". The pedal is not hitting the return stop pad now so I should not have any issues with brake drag. I might have to consider modification to the push rod for additional length. Probably will wait until after engine swap is complete and I can test performance without modification. __________________ Mike 67' GMC Fleetside



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.