Can't bleed rear passenger brake...
 

I am working on a new project a 1979 Corvette - L82 code 4 .... It was parked for over 11 years in a garage... I just replaced all 4 calipers / brake pads and rotors... The rear passenger wheel won't bleed with pedal / gravity or vacuum pump.... All other wheels are fine...

I tried to search online but all I can find are treads where both rear wheels won't bleed...

Thanks....

Did you change the hoses?

And, if you didn't, you may as well get the super-whammerdyne DOT approved braided steel hose units.

Also, you can make yourself a pressure bleeder fairly cheeply. I don't even try to bleed brakes without my pressure bleeder anymore.

A very quick search reveals these guys at a fairly good price: https://www.ebay.com/i/162718832183?chn=ps

make sure you check shipping charges and whatnot.

I've used a Motive pressure bleeder a few times, and it's great (picture attached, the clamp works much better than the silly chain thing it comes with).

I also use a pair of bleeder bottles, also from Motive.

Finally, and you may not hear this suggestion elsewhere, I make sure there is a bit of Loctite on the bleeder screw threads. Not much, and not so that it gets in the hole, but it helps to prevent air from chasing past the threads.


https://cimg7.ibsrv.net/gimg/www.cor...cfc649ef91.jpg

That's kind of a trick question. Do you mean?

Air bubbles continue regardless of which method I use to bleed?
Or no fluid what so ever comes out of the bleeder screw?
Or, the caliper refuses to take any brake fluid, pads / pistons do not move?

No I did not change the hoses, my local auto parts do not have those in stock anymore... I ordered new ones but they have not yet arrived...
I disconnected the metal portion of the line from the bracket on the chassis going to the rubber hose and there is no brake fluid there either... the metal line I tested with the vacuum pump on one side and the other in a brake fluid container and it is clear of obstructions....

Thanks Carriljc
I will order those and return my rubber ones when I get it...

Thanks Bikespace I just ordered the kit plus the 2 bottles from Amazon.... More tools to add to the collection ;-)

Thanks for the reply HeadsU.P.

No fluid at all comes from the line even when it is disconnected from the caliper.... All I can find online is the valve after the master cylinder but that would cut both rear brakes.... All 4 calipers were in really bad shape but the rear ones had no leaks both of the front ones were leaking even without pressure applied on the pedal...
Is there another valve where the line splits in the rear?

Not a valve but a distribution block at the back. Chunk of brass with one pressure line going in and two lines coming out. Seldom have blockage issues though.

Because the rear calipers rubber hoses are "upstream" more so than the fronts I would suspect a collapsed hose like bigbird mentioned. The hoses can look perfectly fine on the outside, but on the inside is another story.

And yes, the Proportioning Valve feeds both rear brakes so that is not the problem in your case.
If the right rear hose is bad, go ahead and replace both rears, or better yet get the 4 pc set. Make sure they're American made.

Thanks Big2Bird

Thanks HeadsU.P.

I am going to disconnect the rubber hose tomorrow to check if the problem is there... if I still can't get any fluid there I will go to the distribution block that Big2Bird mentioned and disconnect there...

Another question... I can't find anyone at the parts stores near me that knows what tool is used to disconnect the metal piping from the caliper I had to use a pressure plier on my old lines and they were already in bad shape... I want to buy the tool so when the new ones arrive I can install it without damaging it as well....

Hopefully it is a collapsed hose, and replacing the hoses fixes your problem. The pressure from the Motive bleeder may force brake fluid through, but you certainly want new hoses anyway.

Let us know how it turns out! Some additional tips include lightly tapping the calipers to get trapped air bubbles out, and always using flare wrenches on the fittings. I found that I needed a crows foot wrench to get the drivers side hose replaced.

https://cimg7.ibsrv.net/gimg/www.cor...899c7888e4.jpg

If you still have a Sears around you, they may have a three piece set of "line wrenches" or flare wrench. Three wrenches = 6 sizes. Can be used on brake-lines, fuel-lines , etc.

Bikespace...

I will post either way tomorrow... Thanks for the tip on the calipers...

Have a great night

No they are all closed here... I am looking online...
I have the flare crown attachments from 9mm to 22mm but they do not fit the rear brakes... the front brake lines I was able to do it without any problems...

I guess I will have to figure out when the new ones arrive the back ones may have been rounded by the previous owner trying to change the calipers... they were in really bad shape...

Thanks HeadsU.P.

https://cimg0.ibsrv.net/gimg/www.cor...e924bba3f9.jpg
Here is a pick of my current attempt to bleed the passenger rear brake line...:-(
It still has the old rotor on it... the new one will arrive monday...

looks like that rotor's been painted … paint will contaminate pads … bad

Start spraying now, the fittings you intend to dismantle later, with PB Blaster.

About the wrenches, maybe your local NAPA. eBay takes too long.

those are still the old pads.... I wanted to test drive the car this weekend... :-) the new parts are arriving little by little ...
The car has not been driven for more than 11 years... I already changed all fluids, spark plugs & wires... I think I am going to need a new carb as well...
The transmission is a surprise... Previous owner told me it was fine but that was 11 years ago when he last used the car...

harbor freight also has flare nut wrench sets

Are you using a bleeder screw for the bottom / outside port? Should be a threaded plug, but that will work.

That is what came with the new caliper.... Should I remove the plug from the old ones?

Jackson, they have it but the smallest size is 10mm and the rear calipers are either 9 or 8mm but since mine were already damaged I don't know exactly what size they are...

Did you put your calipers on backwards? The bleed ports should be at the top (two on the rear calipers, one on the front caliper). At the bottom of the caliper, there is a plug on one side and the line goes in the other side. If you have Delco Moraine calipers, you can confirm by the casting number that you have them mounted correctly.

My caliper (Post #14) probably has the same "paint". G2 epoxy?

EDIT: Nevermind, I see that you have three bleeder valves. The bottom one is just a plug. You need to bleed from the top two.

iirc … c3 bleeders and hoses are not metric

if bleeders are stuck... break em with 6 point socket

No my new ones came with 3 bleed ports and I mounted exactly as the old ones... The brake line enters the caliper on the inside lower port...
My old calipers had the plugs at the bottom port on the outside....

Well, I would. Unless you feel the need to carry around 8 bleeder screws.

Thanks Jackson...

Thanks... the guy that sold me the calipers at Napa told me they were metric... I will stop by harbor freight tomorrow to buy another set... do you know the size needed for the rear lines?

You can use a bleeder screw as the third port plug. Clearly the rebuilder thought that was fine. It should seal just the same, as long as you bleed from the top two ports to get the air out. If you take it out of your old caliper, you'll see the same chamfered tip, that seals with the machined face at the bottom of the hole in the caliper.

You'll need the flare wrenches for the brake hoses and lines, but you can use a standard close-ended 6-point wrench (or even a deep socket to get started) for the bleed valves. I think my valves take a 5/16", but the wrench I have also has a 3/8" end.

maybe napa (fka standard parts) calipers have metric bleeders ? no clue why.

whatever size they are, use right size & type tool, break them open & tighten with 6 point socket or 6 point closed box wrench

I don't recall size of hex on hoses...the flare wrench is also known as a Line wrench...for good reason

also, good quality (eg wagner, raybestos) OE type rubber hoses work very well and may outlast you; I'll certainly go first . Braided stuff not needed.

Brake hoses are date coded. Service life is 10 years. I change them if older than 10.

Thanks Jackson...

Thanks Big2Bird...

At this point I think I will replace the front ones as well... I also had to flush the old brake fluid it was very dark...

Good night everyone...

The problem was not the hose, I disconnected the hose from the line and there is no fluid there either... I will try tomorrow afternoon with the pressure bleeder maybe that will force the fluid and clear the line... I will post the results here...

Have a nice week everyone!!!

I assume you mean no fluid at both ends of the hose when disconnected. So, backtracking more, that leaves the distribution block as the only suspected item left.
Or a pinched / damaged steel line between the D. block and rubber hose.

HeadsU.P. yes correct... The hose is clear of obstructions... I used a large syringe to push fluid thru the hose and it flows free...
Since now there is nothing connected and I have the Pressure Bleeder arriving tomorrow I will try that to see if I can clear the line...

Thanks for all the help!
Have a great week!

And get the correct tubing wrenches. Should NOT be metric. You don't want to rounding off those fitting nuts.

NO METRIC ALLOWED on C3s. Last guy that did that is still serving his 5 yr sentence in San Quinton.

You do realize 81 has both standard and metric fasteners.

I have my hands over my ears. No-no-no-, say it isn't so. Even the bleeder screws too? Ought to be a law.

Thanks, I did not reallze that. Did they do that on the calipers also? Seems like it would create a warehousing nightmare if you were planning to change design within a year or so?

:iagree:

Replacing the alternator requires a full set of both metric and SAE tools. I think the brake parts are all SAE, though, even in 1980.

Check that forward "proportiong vlv-shuttle vlv-distribution Block" also. If you bled really fast, then the Internals may have shifted(as designed) and be blocking flow. Search this forum for info on that.

I do not believe the bleeders changed.
When working on this car, I have both flavors in the roll around.
IE, some ground screws are metric, some not.
The slow change over was dumb.

Yup. And if a dufus used a standard bolt for the alt. pivot bolt, the alt. will cock sideways and cause bad belt alignment.

O.P. has no fluid at right rear but does have fluid at left rear. The Prop Valve only has one line going to the rear so that's fine. He has fluid rearward to the distribution block at the rear axle also. So that leaves the line from the D block to the rubber hose at the RT rear. RT rear hose was clear, but not before that.

And the "Brake" light would be on (or should be), making it easy to spot if that's the problem. Perhaps the blocking valve shifted after the left rear was completed, but before the right rear, so now no more fluid flow?

They make this piece to keep the valve centered (even cheaper at eBay)
https://www.summitracing.com/parts/c...RoCU6EQAvD_BwE

I haven't needed it with the Motive bleeder. Hopefully the OP is able to get to the bottom of this quickly.

Yup, have that nifty little tool myself. As much as they charge for new Prop Valves, that tool should be included. Must cost a whole $2 to make it.

Hello everyone....

I finally had time to work on the car again today.... the problem was the distribution block on the drawing that Big2Bird sent... It was completely clogged once I removed the line and added pressure with the pressure bleeder it cleared at lot of junk from the block.... now it is working.... I think that caliper was not working before they put the car in storage... the brake pads were almost new when compared to the other side....

Thank you guys for your time and knowledge...

Have a great night everyone!

Good deal.

Fascinating. I don't think I've heard that one before. Thanks for following up for us curious folks.

Thanks for the update.

Change out those old hoses

Jackson...

I will just waiting for the set to arrive... I am also replacing the metal lines from the rubber to the caliper... mine are in bad shape and with rounded connectors at the calipers... When the new ones arrive I will have to figure out if they are SAE / Metric and what size... According to everyone here they are SAE and I already pick up the set at harbor freight today....

Have a great night

Take the bleeder screw completely out to see if any brake fluid flows out. If not, the fluid passages drilled in the caliper may not connect...or were drilled improperly. If you get fluid out, look the bleeder screw over. Maybe it wasn't drilled.

I also am doing my rear brakes and cannot get any fluid down to the drivers rear. I'll check the distribution block tomorrow. Thanks

I used to use the Mity-Vac to bleed my brakes. It would pull air back into the system from around the bleeder threads. I solved it by sealing around the bleeders with petroleum jelly.

Switched to a Motive bleeder and never had another problem bleeding brakes.

Just as an update on my rear brakes in case this helps someone in the future. We started cracking the lines working our way away from the caliper. Got to the junction block and rubber hose and had fluid, meaning the rubber hose was suspect. Took it off and it was completely clogged and could not be blown out. Grabbed another hose from the autoparts store and it finally had fluid to the caliper.