Bleeding problem??

[SCOTI]

OK, I'm bleeding the brakes on the 74 & I'm running into something weird.

Backround first: I replaced the old front calipers & rotted brake lines up front during the suspension rebuild. While apart, I also installed new 'speed bleed' bleeder screws so I could bleed the system by myself if needed. Not being sure of how well these bleeders work, I got my better half to assist.

I decided to go ahead & bleed all 4 corners for ease of mind. When opening the rear bleeders, she says the pedal isn't sinking (yet I'm getting fluid). When bleeding the fronts, everything looks right. Initially I got alot of air to the jar, then the amounts decreased w/each subsequent bleed.

I've made 3 complete rotations around the truck, & I'm bleeding each corner 3 times before moving to the next, & yes, I'm moving from farthest cylinder to closest so my rotation is correct. I tell her when & she slowly presses the pedal & tells me when she's out of travel. I open the bleeder screw & allow fluid out, then close it & let her know it's OK to slowly release the pedal.

After 3 times around (& 3 bleeds @ each cylinder, each time), checking mstr cyl levels after each cylinder, there's still isn't decent pedal. Now I've done a rebuild/disc swap on my 68 (the same methods, same parts) w/o issues & I've done others so I'm confident in my ability, but this is pissin' me off. Oh yeah, she assisted me on the 68 so I'm confident in her as well!

What am I missing here????????????

[Russell]

With my 80, it felt really spongy at first... Take it out onto the driveway, and get moving very slowly and press the brakes down slowly, you'll find that each time you stop it will get stiffer. At least it did in my case...

[old Rusty C10]

when ya did the front replacement of the calipers and lines did the master go dry? if so ya gotta re bleed the master

[SCOTI]

Nope. When I popped the master cyl cover there was still @ least 50% fluid inside.

I think I might go ahead & re-bleed the master anyway (it's not like it's difficult or time consuming) & that will ensure no air, then I'll go a few more time around the truck.

Soooo close, j u s t w a n t to d r i v e it . . ..... & put my wheels/tires on!!!!

[SCOTI]

Well, I bled them again & even followed a tip on swervins site about waiting @ least 15 secs between but I still have a spongy pedal. Oh well, I went ahead & drove it around the block . . .... the front tires damn near rubbed the tops of the wheelwells the whole trip (burned all the undercoating/paint off).

So looks like I'll trim the stock coils a little less than what these were cut. Sucks, 'cause it sure sat right . Guess I'll get a new mstr cyl & booster for it this weekend since I replaced everything else up front, then exhaust & alignment.

[swervin ervin]

I hate it when you can't get the things bled right. A lot of times it can be bad wheel cylinders, brake lines, and for sure master cylinder. A master cylinder is fairly cheap and it probably needs a new one anyway.

My vote for what's wrong would be the master cylinder. I've found out if you can't the air out no matter how many times you bleed the brakes, it's usually the master cylinder.

Good luck with it.

[N2TRUX]

Scoti,
This won't matter now, but here's a trick I learned for bleeding brakes by myself, or with another person. Get a small piece of vacuum line about a foot long. Put your boxed end wrench over the bleeder valve, and slip ther vacuum line in the valve.

Submerge the other end in a small clear container of clean brake fluid. Now you can open the valve and press the pedal down. As long as the one end is submerged in the fluid, it won't draw air back in.

I agree with Mike on this one. I think you either have air trapped in the master cylinder, or you have a blown seal somewhere. If the master cylinder is blown to the inside, it won't leak fluid, but it will give a spongy pedal.

Spongy pedal or not, do the brakes feel like they are working?

BTW- Roger and Keith have been trying to get in touch with you.

[SCOTI]

Hey Ken . . .... that's a damn fine idea, too bad I was already doing exactly that (lol). 7/32 vac line submerged in a small clear jar so I can watch/listed for air bubbles.

I've been by the shop a couple of times but they haven't been there (prob out @ SOS). Between my hrs @ work & funerals the past 2 Saturdays + trying to get the 74 finished, there doesn't seem to be enough time. Hell, I figure the Ramblers got a nice, slick engine compartment by now . . .... empty, but slick.

As you can tell by my previous post, it's too freakin' low to drive . I'll try just lopping off 1 coil this time & hope that works. I still have to mount the 1.25" sway bar & I'll be picking up the new mstr cyl/pwr booster tomorrow after work (if I ever get out of work . . .... guess where I am @ this moment?????). I will post some finished pics as soon as I can drive it. Those 20's look sweet tucked up in the back!

[SCOTI]

Fri night after work, I decided to just pull the lines off & bleed the master cyl on the truck & sure enough, there was air in the lines (I was 110% sure the level didn't get too low but we all know how reliable that can be) so I bolted everything back together & after the first round of bleeding . . .... no air in the lines except for the farthest cylinder (pass rear). Six + ounces of brake fluid later, I'm still getting some air bubbles from that cylinder. I guess there's a leaky wheel cylinder or something similar.

Anyway, the pedal feel is much better so now it's time to switch out the front springs for something that will allow me to actually drive it down the road. I can't wait until tomorrow am.

To be continued . . .....

[N2TRUX]

Glad to hear you got your problem solved. Well almost anyway. As I said when we talked, I have never had air trapped that deep in a master cylinder, but I hear once it's there, it doesn't want to come out....