My first car was a '66 Satellite convertible. Manual brakes and steering, 273 2bbl, 3 on the tree. I thought the brakes were fine, but I did miss power steering.
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High pedal pressure with KH disc brakes
- Thread starter Bob Jasinski
- Start date
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Dana, Do you think I may have the wrong pedal to MC rod? They didn't offer the dual pot MC in '65 so parts book is of no help. Does your '67 have a single MC or dual?
Just a data point for you:
So something must be wrong with your setup. Maybe try to warranty the master and see if a new one works better? Proportioning valve? Effed up rubber lines? Stuck caliper pistons? Pinched metal line? Misajusted rear brakes? There is not a ton to the system, so just keep going through it and the problem will reveal itself.
You'll like the brakes when they are working correctly.
- 72 Swinger with manual front K-H setup.
- 15/16" Master (p/n RSD-DBMC15) -- no booster.
- Adjustable pushrod (p/n RSD-RC14)
- Stock(ish) rotors and middle-of-the-road pads from NAPA
So something must be wrong with your setup. Maybe try to warranty the master and see if a new one works better? Proportioning valve? Effed up rubber lines? Stuck caliper pistons? Pinched metal line? Misajusted rear brakes? There is not a ton to the system, so just keep going through it and the problem will reveal itself.
You'll like the brakes when they are working correctly.
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Vames, Thanks for the feedback. My car is basically done except for this brake problem and front end alignment. I see you used a different MC, RSD-DBMC15, mine is a 15/16 Raybestos 36406 15/16". Also I see you're using an adjustable pushrod, that's what I needed to know. I'm using a '67 prop valve, new hoses, all new lines, no stuck calipers that I can tell, bought them a while ago but they're new rebuilds from the parts store. The car stops true, does not pull, but low pedal and a lot of leg force. I may have a bad (new MC), but when the pedal is in the rest position, I can still lift it about a 1/4" -3/8" then it stops at the brake switch. I'm pretty sure it could stand a longer pushrod. Why did you decide to use the adjustable pushrod? Were you having the same problem I have with the low pedal?
Honestly it was like 30 years ago -- most likely someone on the old slantsix.com advised that I'd need an adjustable pushrod so I put one in. Aside from adjusting it to make sure my brake light turned off at rest, it all worked fine right away, so I never had a problem like yours.
Factory dual. all 67 and up have dual masters. there are multiple lengths of push rods @Oldmanmopar posted a photo showing several side by side.
That is totally normal. also the brake light MIGHT (its that way on 67 and up) be attached to an L shaped bracket that has an adjusting bolt accessible from the passenger side of the steering column
all a longer pushrod will do is move the pedal higher to start with and then when you build pressure it will be farther from the floor. The brake light switch will have to be adjusted to compensate
JUST for a test. if someone applies the brake and all 4 wheels are off the ground and the trans is in neutral, E brake is off, check for the ability to rotate each tire. It might be more accurate to do this with a 2x4 between the brake pedal and the front seat. if the pedal is pressed too hard there will be no rotation at all. but at some point you should be able to just rotate the tires. looking for all 4 to be about the same from a force perspective. VERY unscientific test.
could the problem on these (multi KH posts) be something about the crossover tube?
restriction favoring inside pistons, or front to rear?
most likely just air
maybe remove the caliper and fill/bleed in different angles,
tap with a screwdriver handle kinda thing
also there is a hose barb on the bleeder for a reason
tube into cup (actually juice bottle), slow full deep strokes,
love it like ya mean it,
and a quick pullout, (release of pedal)
not pump it up squirt repeat
also you can bench bleed calipers when ya do the MC
(A new MC always needs turned with the ports up and a squirt or two before bench bleed)
restriction favoring inside pistons, or front to rear?
most likely just air
maybe remove the caliper and fill/bleed in different angles,
tap with a screwdriver handle kinda thing
also there is a hose barb on the bleeder for a reason
tube into cup (actually juice bottle), slow full deep strokes,
love it like ya mean it,
and a quick pullout, (release of pedal)
not pump it up squirt repeat
also you can bench bleed calipers when ya do the MC
(A new MC always needs turned with the ports up and a squirt or two before bench bleed)
Dave999
Well-Known Member
are the slider calipers sliding on their pins properly?
were the new pads flat? and can the new pads slide along with the caliper?
did you clean the packing wax off the new front rotors? any wax or grease now on pads.
Have the rotors been correctly broken in?
do you have a brake bias? if not you will probably need one.
do you have a brake safety switch in the distribution block or master cylinder? is it stuck? and hence half the system switched off?
not being blunt.... these are all issues i created for myself at some point in the last 20 years
dave
were the new pads flat? and can the new pads slide along with the caliper?
did you clean the packing wax off the new front rotors? any wax or grease now on pads.
Have the rotors been correctly broken in?
do you have a brake bias? if not you will probably need one.
do you have a brake safety switch in the distribution block or master cylinder? is it stuck? and hence half the system switched off?
not being blunt.... these are all issues i created for myself at some point in the last 20 years
dave
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OP said KH 4 piston fixed
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Op said 67 proportioning valve
Thanks much for the tips. I've read a lot about the KH conversions for early A bodies but this is the first confirmation about the possible need for an adjustable rod. There's a good deal of information
Factory dual. all 67 and up have dual masters. there are multiple lengths of push rods @Oldmanmopar posted a photo showing several side by side. This is encouraging, I've ordered the adjustable pushrod from Summit.
all a longer pushrod will do is move the pedal higher to start with and then when you build pressure it will be farther from the floor. The brake light switch will have to be adjusted to compensate. At this point that is exactly what needs to happen, adjusting the brake light switch is not an issue
JUST for a test. if someone applies the brake and all 4 wheels are off the ground and the trans is in neutral, E brake is off, check for the ability to rotate each tire. It might be more accurate to do this with a 2x4 between the brake pedal and the front seat. if the pedal is pressed too hard there will be no rotation at all. but at some point you should be able to just rotate the tires. looking for all 4 to be about the same from a force perspective. VERY unscientific test.egarding the higher pedal. I'll try it, I have a lift so easy to do.
As Dana mentioned this is early KH discs, no sliding pin. I've tried 3 different sets of new pads, The set in it now (used) came with the swap meet used KH calipers, which were turned over as cores at the parts store I bought rebuilt replacement KH calipers. No difference in brake function between any of the pads. Rotors have about 170 miles on them. Yes I have '67 brake bias (prop) valve, new from Mega Parts. No brake safety switch, no light used in the '67 prop valveare the slider calipers sliding on their pins properly?
were the new pads flat? and can the new pads slide along with the caliper?
did you clean the packing wax off the new front rotors? any wax or grease now on pads.
Have the rotors been correctly broken in?
do you have a brake bias? if not you will probably need one.
do you have a brake safety switch in the distribution block or master cylinder? is it stuck? and hence half the system switched off?
not being blunt.... these are all issues i created for myself at some point in the last 20 years
dave
Crossover tubes new, calipers seem to be pressing evenly, both. I will try the cup of brake fluid with the hose in it, I have bled the system at least 5 times, by gravity, by wife pressing down pedal close release again, and by vacuum pull from each wheel cylinder. I did bench bleed the MC, it has not run dry during any of the process. I've ordered the adjustable pushrod from Summit, gonna try that next. If that doesn't fix the issue I may replace the MC, but it is new.
Bob, please let us know your results after installing the new pushrod!
This is for 1967 and up BUT it might be the same as 66 and older
OK, so here's how it went. I bled the calipers again, several times with my wife at the pedal. She's done this with me many times going back years, we met in High School. I did get some more air out, small amounts. UPS arrived with my adjustable pushrod from Summit (see post #53). Gotta say Summit is prompt, put in the order in yesterday about 2:00 pm, arrived about noon, less than 24 hrs! Came out of Reno. Removed the old one, compared it for length and fit, put it in, adjusted it, and it did help my issue. Came with the tip on the end but made with a vinyl like clear plastic not rubber. Adjusted it about 1/8-3/16" longer than the original, and readjusted the brake light switch. pedal is acceptable now, foot pressure probably about the same but feels better with a higher pedal. The replacement rod is well made, easy to adjust in place and has "knockers" on the head for the brake switch, although my brakes switch still actuates from the brake arm. Brakes are better now but I'm still thinking about a booster.
Dana, Could you elaborate a bit about the pictures? Are you showing the brake light adjustments? The '65 is different.
Yes 67 up adjustment. Hoped that 66 and older was similar
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