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Discussion Starter #1
I am trying to still wrap up the brakes on my 1969 XR7 S code with power front discs and rear drums. The fronts bled well last night. I consider them done. I could NOT bleed the rears. I started on the passenger side and got 2 "pump and holds" of dirty fluid out and then she stopped bleeding. Pressure was not that good on the brake pedal as well. The drivers side wouldn't bleed either. This is also the line that I am going to replace from the splitter block on the axel. I tried to swap out the rubber tube for a SS line and could not turn the connector for the line on the passenger side at the block. It is rusted and the whole tube twists. So a new pre-bent line is ordered and will be replaced with the SS line soon.

My thinking is that the master cylinder is bad. I can open the line from the splitter block to the drivers side,(no rust) and with pumping the brake pedal nothing is coming out of the splitter block so there is either an obstruction in the line forward of this point or there is no pressure from the master cylinder, and there is fluid in the brake resivior.

I have owned this car for 3 months. Have zero history of prior repairs. Not even sure if I had rear brakes working prior to doing the brakes. Could a line get clogged with a piece of debris that was in the resivior? What about the brake proportioning valve?

Any thoughts to help trouble shoot would be great. I am planning on starting with the master cylinder soon.

Thanks...............Bill
 

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If you got fluid out of the rear passenger side I would think the master cylinder and proportioner are good? I would disconect prior to the splitter on the axle and see what you get then go from there before I started in rebuilding the other stuff. Course if you have one line that is bad you probably ought to replace them all. You could get a clog from anywhere.
 

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The rubber line from the chassis to the tee (splitter) on the differential housing could be plugged or partially plugged, especially if exhaust has been routed too close to it. been there, done that.:)
 

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Discussion Starter #4
Correct, fluid did flow out the passenger side during the first 2 cycles of pumping/loading the line with pressure, and releasing the bleeder, then it stopped, on both sides in the rear. The block on the rubber line also did NOT allow flow from it as well from that point forward. So your feeling is that the Master cylinder and proportioning and distrubutioning valves are good. It seems easier to try to open the rear line more forward and see where I can get some bleeding from it.

Nice though and I like it. I just rewatched Don's rebuild video of the proportioning and dist valve paying more attention to it.
If you got fluid out of the rear passenger side I would think the master cylinder and proportioner are good? I would disconect prior to the splitter on the axle and see what you get then go from there before I started in rebuilding the other stuff. Course if you have one line that is bad you probably ought to replace them all. You could get a clog from anywhere.
 

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Discussion Starter #5
What happens from the exhaust? Are you saying it melts the line somehow?
The rubber line from the chassis to the tee (splitter) on the differential housing could be plugged or partially plugged, especially if exhaust has been routed too close to it. been there, done that.:)
 

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My experience was with an aftermarket dual exhaust installation. Left side exhaust pipe was routed very close to rubber brake hose. Hose didn't look bad, but had deteriorated on the inside & was partially plugged. Found new hose and splitter (Tee) at NAPA. If the hose is original, or looks real old, I'd replace it for safety's sake anyway.
 

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make sure rear brakes are adjusted up---you can make them solid for bleeding---try bleeding both the front and rear @ the same time
doctordesoto
 

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Discussion Starter #8
Not sure what you are saying here. In the rear I have replaced the shoes, all springs and fasteners and the cylinders. Everything is new. The shoes are adjusted to allow the drum on not too loose and not hitting them to hard either. I am not sure why bleeding both the front and rear at the same time will help. The fronts are done. Good to go. They are two separate systems with separate reserviors, aren't they?
make sure rear brakes are adjusted up---you can make them solid for bleeding---try bleeding both the front and rear @ the same time would help. doctordesoto
 

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Discussion Starter #9
My experience was with an aftermarket dual exhaust installation. Left side exhaust pipe was routed very close to rubber brake hose. Hose didn't look bad, but had deteriorated on the inside & was partially plugged. Found new hose and splitter (Tee) at NAPA. If the hose is original, or looks real old, I'd replace it for safety's sake anyway.
Besides after taking the drums off and seeing that this project needed to be done, the car was able to stop. There were brakes. Maybe only the fronts were working though.
 

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Old man is telling you the right thing.

The rubber brake hoses fail from the inside out. The liner of the hose separates from the casing. Fluid goes behind the liner and then pushes the liner shut. If you let it sit for a while you will get a little flow and then it stops when you start to pump the brakes.

You need to disconnect the hard line where the rubber tube to the axle connects. Verify that you are getting good flow here. The hardline rusts from the inside out and frequently becomes clogged when you try to use it after being parked for a long time.

After you have done a few cars you will develop a list of stuff that you just replace with out even thinking about it. This is one of those things.
 

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That's similar to what I found on my 67. The front brakes were ok and the rear brakes looked brand new. Inspection found rear wheel cylinders corroded inside. Apparently PO had replaced wheel cylinders but had not checked brake lines. I replaced all rubber lines after finding this problem, then flushed all lines with new fluid until it came out clean.
 

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For the price and the piece of mind I am currently replacing every brake line on the car, I will also rebuild the proportining valve after seeing the video from WCCC.
 

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Follow Bills advice - I bet you find all kinds of gunk inside the lines. DOT 3 fluid needs to be flushed regularly as it will absorb moisture and then that slowly rots the lines inside! Converting to silicone fluid prevents that - you have to be careful that the hoses and rubber components are compatible which "should" be if all new....not china made stuff though
 

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Discussion Starter #14
This is making some sense. I will try this. I have the replacement SS hose for the rubber one. I am planning on changing this as well as the rusted brake line to the right rear cylinder. I hope there is flow when I disconnect the rubber hose. If not, then the master cylinder will get changed and proportioning valve and distribution block are also going to get rebuilt too
Old man is telling you the right thing.

The rubber brake hoses fail from the inside out. The liner of the hose separates from the casing. Fluid goes behind the liner and then pushes the liner shut. If you let it sit for a while you will get a little flow and then it stops when you start to pump the brakes.

You need to disconnect the hard line where the rubber tube to the axle connects. Verify that you are getting good flow here. The hardline rusts from the inside out and frequently becomes clogged when you try to use it after being parked for a long time.

After you have done a few cars you will develop a list of stuff that you just replace with out even thinking about it. This is one of those things.
 

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Discussion Starter #15
I got my new pre-bent line yesterday for the passenger rear, and put it in with the new SS hose with splitter block and she bled right out. NICE!! Great suggestion. Brakes are done for now. Not a complete system overhaul, but quite a bit was done. Besides the booster, master cylinder and proportioning valve, all is new.
Thanks again.
My experience was with an aftermarket dual exhaust installation. Left side exhaust pipe was routed very close to rubber brake hose. Hose didn't look bad, but had deteriorated on the inside & was partially plugged. Found new hose and splitter (Tee) at NAPA. If the hose is original, or looks real old, I'd replace it for safety's sake anyway.
 
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