brakes go to floor

[K10-Kansas]

Originally Posted by geezer#99

Quite a difference in air bubbles.
Which reservoir is which?

That small reservoir is the back brakes so I assume my old brake tubing that I cut and was using for this test wasn't getting a good seal.

[geezer#99]

That’s what’s nice about those kits, they seal and are easy to use.

[K10-Kansas]

I pulled the proportioning valve brake light grounding connection to stabilize the internal slide while bleeding the back brakes and have a question. Is the o-ring supposed to be midway on the threads like that?

[geezer#99]

No, but when you put it back in the o ring will roll back up.
Or just roll it up by hand.

[K10-Kansas]

Originally Posted by geezer#99

No, but when you put it back in the o ring will roll back up.
Or just roll it up by hand.

Great thanks. I'll roll it back up then.

[K10-Kansas]

I replaced the master cylinder brake lines because I felt that they weren't getting a good seal. They were 51 years old. Bench testing the master cylinder shows it working well. I adjusted the back drums and they are so far out now that it is really tough to get the drums on and off. I put the bleeder bolt in the proportioning valve. Bled all of the lines again. I added fluid to the master cylinder everytime it got down halfway. That happened about 5 times. And the brakes still go to the floor. I can build up a little bit of pressure if I pump the brakes several times but even doing that, it doesn't stop the wheels from spinning. I've got it up on stands with the tires off.

Any suggestions?

[cadillac_al]

It sounds to me like this master cylinder is either defective or damaged. I guess they can be damaged by having the pedal go to the floor too many times. It has never happened to me though. I would try another one and hope for the best.

[mongocanfly]

Can you get some pics of all the brake components on the truck? Maybe somebody can spot something
I know a guy that has a scout that had similar issues...he had his front calipers on backwards.....it wasn't until he shared pics that it was spotted

[K10-Kansas]

Originally Posted by mongocanfly

Can you get some pics of all the brake components on the truck? Maybe somebody can spot something
I know a guy that has a scout that had similar issues...he had his front calipers on backwards.....it wasn't until he shared pics that it was spotted

Yeah, definitely as soon as I get home I'll take some pictures.

How would having calipers on backwards cause the brake pedal to sink to the floor?

[Just call me Sean]

The bleeder has to be on top. If they're on the wrong side the bleeder will be on the bottom and you won't be able to get all the air out.

[K10-Kansas]

I want to preface what I'm about to say, with an face-saving explanation. So,,,, I didn't know the bleeded had to be on top. I looked at my new set of calipers last week one said R so I stuck it on the passenger side and stuck the other on the driver's.

After reading Mongo's post I checked mine and sure enough, while one caliper for some crazy reason does in fact have an R on it, it also has an L. The other has an L only. I had the bleeders on bottom. I reversed them, bled the brakes and it's working perfect!

Thanks a ton Mongo!

[mongocanfly]

Sweet!!!!!!!!!

[72c20customcamper]

Originally Posted by K10-Kansas

I replaced the master cylinder brake lines because I felt that they weren't getting a good seal. They were 51 years old. Bench testing the master cylinder shows it working well. I adjusted the back drums and they are so far out now that it is really tough to get the drums on and off. I put the bleeder bolt in the proportioning valve. Bled all of the lines again. I added fluid to the master cylinder everytime it got down halfway. That happened about 5 times. And the brakes still go to the floor. I can build up a little bit of pressure if I pump the brakes several times but even doing that, it doesn't stop the wheels from spinning. I've got it up on stands with the tires off.

Any suggestions?

Seams weird that you had brakes when you drive it off the trailer . Did you change out the front calipers ?

[K10-Kansas]

Originally Posted by 72c20customcamper

Seams weird that you had brakes when you drive it off the trailer . Did you change out the front calipers ?

Yeah, the progression of events went: replaced the brake pedal housing assembly, adjusted the clevis on the pushrod, moved the booster a dozen times putting in the steering column, blew the front left brake line, put on new brake line, tried to bleed the brakes, broke both front bleeder screws, bought new calipers and put them on upside down, didn't bench bleed new master cylinder (that i didn't even need), put calipers on correctly, bench bleed master cylinder. And then everything worked.

The brakes did seem to work well coming off the trailer and then didn't work well up on stands. The only reason I can guess why is that i had the pedal pushrod and clevis adjusted too short. But who knows because then I immediately blew a brake line.