Brake Pedal free travel? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Solver · 09-25-2004, 11:04 PM

I have several trucks and it seems some take more braking pedal distance to engage brakes and some you just barely push down and it is already braking. Is there an adjustment in the pedal linkage to correct to much free travel?

Rusty Rider · 09-26-2004, 12:35 AM

If they are all power I would say that the long travel ones might need a new master cyclinder or a rebuild. The first part of break enggagment is the rear and the truck will still stop with no back breaks with little notice being that about 70 % of the breaking is front besides for the traval of the break padal. I would jack one up and and drop it in gear with the break on. hit the gas a little to see if they are working.

krue · 09-26-2004, 02:15 AM

You can adjust the pedal travel in two places. The first to try is the pedal to booster/master cylinder (depending on whether you have power brakes). After adjusting this make sure to adjust your brake light switch. If you have power brakes there is a rod between the booster and the master cylinder that could need adjusting (not likely unless you added the booster or replaced m/c).

toddtheodd · 09-26-2004, 02:52 PM

I've replace my m/c... do you have a picture of this rod?
Todd

cdowns · 09-26-2004, 03:31 PM

bad(old) brake fluid can also be a cause of excessive brake pedal travel

krue · 09-26-2004, 03:37 PM

Sorry no pics of the rod, didn't have digital camera when I added my booster and I didn't think to take pics when I replaced my m/c.

toddtheodd · 09-26-2004, 04:12 PM

Can I adjust this rod without taking the m/c or booster off?

Jimmy72custom · 09-26-2004, 04:43 PM

A low pedal could be from brake shoes that are not adjusted properly. The self adjusters rust and freeze up, this is common.

Longhorn Man · 09-26-2004, 06:58 PM

To figure if it is misadjusted shoes or the pushrod, depress the pedal with your index finger. if it swings easily, then you are not moving any brake fluid, and the pushrod is too short.
If your finger won't move the pedal down, then your shoes need adjusting.
To adjust the rod (which is common in a M/C swap, and the instructions shoulda been in the box) you'll need to unbolt the master, and pull it off...no need to remove the lines, they will flex enough. Pull the little chrome rod out. It'll liik somewhat like an engine pushrod (ay least on one end...it has been about 5 or so years for me) one end is adjustable. You don't want to take up all the slack. There is sipposed tp be a fraction of an inch freeplay between the rod and the piston of the M/C, this is to allow for expansion of the brake fluid as it heats up.
Adjust it, install M/C, tighten it down, and check the pedal freeplay again....same way as before. I would look for 1/4 inch or so...again, it has been 5 years for me, so I may be off a little.
The main thing to look for is if it is too tight, or not enough clearance. Run the truck down the road, heating things up pretty good. (some hard stops oughta do the trick) and then run it 70MPH or so down the freeway.
If you smell brake shoes burning, or the truck looses it's pep....or if the rear tires lock up when you touch the pedal, then you'll need to shorten that rod again.
It may take a few tries to get it where you want it. I had tried to get rid of all play , and it just is not possible.
If some one has measurements...please add them on here, it has been a while since I have done this...but the 1/4 inch I said here on the pedal sounds about right, maybe a little on the loose side.

toddtheodd · 09-26-2004, 07:03 PM

OK. Just went and checked it and it moves almost half and inch to an inch without any pressure. Makes a click sound when it hits something (I did this with the motor off) so that must be when the rod hits the m/c.
Looks like I know what I'm going to be doing on my weekend (monday / tuesday)

. I finally have something to do this weekend.
Todd

09-25-2004, 11:04 PM	#1
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Brake Pedal free travel? I have several trucks and it seems some take more braking pedal distance to engage brakes and some you just barely push down and it is already braking. Is there an adjustment in the pedal linkage to correct to much free travel? __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

09-26-2004, 12:35 AM	#2
Rusty Rider Registered User Join Date: Aug 2004 Location: Martinsburg, W.V. Posts: 85	If they are all power I would say that the long travel ones might need a new master cyclinder or a rebuild. The first part of break enggagment is the rear and the truck will still stop with no back breaks with little notice being that about 70 % of the breaking is front besides for the traval of the break padal. I would jack one up and and drop it in gear with the break on. hit the gas a little to see if they are working. __________________ 72 long fleet (WIP) 00 Astro every day

09-26-2004, 02:15 AM	#3
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	You can adjust the pedal travel in two places. The first to try is the pedal to booster/master cylinder (depending on whether you have power brakes). After adjusting this make sure to adjust your brake light switch. If you have power brakes there is a rod between the booster and the master cylinder that could need adjusting (not likely unless you added the booster or replaced m/c). __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

09-26-2004, 03:31 PM	#5
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	bad(old) brake fluid can also be a cause of excessive brake pedal travel __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

09-26-2004, 03:37 PM	#6
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	Sorry no pics of the rod, didn't have digital camera when I added my booster and I didn't think to take pics when I replaced my m/c. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

09-26-2004, 02:52 PM	#4
toddtheodd The oddest Todd around Join Date: May 2004 Location: Miami, Florida Posts: 1,418	I've replace my m/c... do you have a picture of this rod? Todd

09-26-2004, 04:12 PM	#7
toddtheodd The oddest Todd around Join Date: May 2004 Location: Miami, Florida Posts: 1,418	Can I adjust this rod without taking the m/c or booster off?

09-26-2004, 04:43 PM	#8
Jimmy72custom Registered User Join Date: Apr 2004 Location: Willits Ca Posts: 261	A low pedal could be from brake shoes that are not adjusted properly. The self adjusters rust and freeze up, this is common.

09-26-2004, 06:58 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	To figure if it is misadjusted shoes or the pushrod, depress the pedal with your index finger. if it swings easily, then you are not moving any brake fluid, and the pushrod is too short. If your finger won't move the pedal down, then your shoes need adjusting. To adjust the rod (which is common in a M/C swap, and the instructions shoulda been in the box) you'll need to unbolt the master, and pull it off...no need to remove the lines, they will flex enough. Pull the little chrome rod out. It'll liik somewhat like an engine pushrod (ay least on one end...it has been about 5 or so years for me) one end is adjustable. You don't want to take up all the slack. There is sipposed tp be a fraction of an inch freeplay between the rod and the piston of the M/C, this is to allow for expansion of the brake fluid as it heats up. Adjust it, install M/C, tighten it down, and check the pedal freeplay again....same way as before. I would look for 1/4 inch or so...again, it has been 5 years for me, so I may be off a little. The main thing to look for is if it is too tight, or not enough clearance. Run the truck down the road, heating things up pretty good. (some hard stops oughta do the trick) and then run it 70MPH or so down the freeway. If you smell brake shoes burning, or the truck looses it's pep....or if the rear tires lock up when you touch the pedal, then you'll need to shorten that rod again. It may take a few tries to get it where you want it. I had tried to get rid of all play , and it just is not possible. If some one has measurements...please add them on here, it has been a while since I have done this...but the 1/4 inch I said here on the pedal sounds about right, maybe a little on the loose side.

09-26-2004, 07:03 PM	#10
toddtheodd The oddest Todd around Join Date: May 2004 Location: Miami, Florida Posts: 1,418	OK. Just went and checked it and it moves almost half and inch to an inch without any pressure. Makes a click sound when it hits something (I did this with the motor off) so that must be when the rod hits the m/c. Looks like I know what I'm going to be doing on my weekend (monday / tuesday) . I finally have something to do this weekend. Todd



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