Master cylinder to proportioning valve hoses

[Musicars]

Came home tonight and was backing into my driveway when I decided to park it and have my wife sit in the driver's seat and push the brake pedal so I could check out the brightness of the new LED bulbs I installed during the day. She yells something about the pedal going to the floor. Sure enough there is no line pressure, therefore no brakes, I have a dash warning light on, and fluid dripping out just inside the driver's side front tire. This could have happened 5 minutes earlier in traffic.

I found the front hose, of the two hose that run from the master cylinder down to the proportioning valve, was leaking badly. It appears to be similar to a brake hose that would run to a caliper and has a stainless steel mesh armor. Right where it turns away from the fender well and heads to the valve it leaks.

Maybe I am searching using the wrong terms but I can't find any part numbers or diagrams for these hoses. Does anybody know if these are available?

Also, this is a 2006, how tough are these to bleed by yourself?

I have no problems bleeding when it involves a downstream part like a caliper or wheel cylinder but I am worried about air at the beginning of a ABS system.

 

[Sam Harris]

Came home tonight and was backing into my driveway when I decided to park it and have my wife sit in the driver's seat and push the brake pedal so I could check out the brightness of the new LED bulbs I installed during the day. She yells something about the pedal going to the floor. Sure enough there is no line pressure, therefore no brakes, I have a dash warning light on, and fluid dripping out just inside the driver's side front tire. This could have happened 5 minutes earlier in traffic.

I found the front hose, of the two hose that run from the master cylinder down to the proportioning valve, was leaking badly. It appears to be similar to a brake hose that would run to a caliper and has a stainless steel mesh armor. Right where it turns away from the fender well and heads to the valve it leaks.

Maybe I am searching using the wrong terms but I can't find any part numbers or diagrams for these hoses. Does anybody know if these are available?

Also, this is a 2006, how tough are these to bleed by yourself?

I have no problems bleeding when it involves a downstream part like a caliper or wheel cylinder but I am worried about air at the beginning of a ABS system.

Yikes! Glad you and your wife are ok.

 

[Doubeleive]

can you post a picture of where it is leaking?

 

[Musicars]

can you post a picture of where it is leaking?

Here are two pictures. I already cleaned off the fluid but the leak is within an inch of the arrow. Can't tell exactly since it is under the braided cover.

 

[Musicars]

No idea why the pictures came up twice.

 

[CountryBoy19]

That's a single assembly with the hard line isn't it? If so, it should be easy to find that part... you may have to go to the dealer...

 

[Musicars]

That's a single assembly with the hard line isn't it? If so, it should be easy to find that part... you may have to go to the dealer...

It appears to be flexible in the middle with a hard line and nut at each end.

Usually I can at least locate the part or a picture on ebay or elsewhere on the Internet, then I can find a part number. I can't find anything anywhere on this. I'll start making calls today. Thought this would be a simple replacement.

 

[Doubeleive]

looks like a front brake line but cant tell from your picture if it is the left or right, but if you go to rockauto, select your make, year, model: then there will be a search box come up, just type in brake line. then it will bring up all matches with pictures
for example I just did chevy/2004/suburban 1500/brake line
https://www.rockauto.com/en/catalog...1424191,brake+&+wheel+hub,hydraulic+hose,1792

 

[Musicars]

looks like a front brake line but cant tell from your picture if it is the left or right, but if you go to rockauto, select your make, year, model: then there will be a search box come up, just type in brake line. then it will bring up all matches with pictures
for example I just did chevy/2004/suburban 1500/brake line
https://www.rockauto.com/en/catalog...1424191,brake+&+wheel+hub,hydraulic+hose,1792

Thanks, but that is not it. It is the Master Cylinder to Proportioning Valve Pipe. I just found out from the dealer that it is discontinued. He gave me the part number, 21998445, but I can't find any anywhere. I 'll have to make a regular line with a loop in it for flex. Maybe when I take the old one out I can find someone to make one up like the original.

 

[Doubeleive]

junk yard will have one

 

[Musicars]

junk yard will have one

Considering that. The problem is I would have to find an intact truck with that same brake set up. There are several different versions and, of course, each one uses different lines. There are not that many yards around here that inventory complete trucks anymore. We lost one of the bigger U-Pull yards last year. Down to a couple with decent inventory and one really small one. The time it takes for such a simple part is frustrating. I will eventually come up with something.

 

[Doubeleive]

Considering that. The problem is I would have to find an intact truck with that same brake set up. There are several different versions and, of course, each one uses different lines. There are not that many yards around here that inventory complete trucks anymore. We lost one of the bigger U-Pull yards last year. Down to a couple with decent inventory and one really small one. The time it takes for such a simple part is frustrating. I will eventually come up with something.

there might be a vin specification that uses it. but you could also try contacting some of the guys that are parting out the same vehicle on ebay they just list the vehicle and you can just ask them if that part is available.

 

[CountryBoy19]

Considering that. The problem is I would have to find an intact truck with that same brake set up. There are several different versions and, of course, each one uses different lines. There are not that many yards around here that inventory complete trucks anymore. We lost one of the bigger U-Pull yards last year. Down to a couple with decent inventory and one really small one. The time it takes for such a simple part is frustrating. I will eventually come up with something.

I've got a yard "back home" I go to when I visit family. Not big but he has 4 vehicles similar to mine, I use him for lots of parts. I would happily pull and ship to you. Unfortunately, I don't think we'll be going to visit family until March, which doesn't really help you if you have a leak now...

 

[Musicars]

I've got a yard "back home" I go to when I visit family. Not big but he has 4 vehicles similar to mine, I use him for lots of parts. I would happily pull and ship to you. Unfortunately, I don't think we'll be going to visit family until March, which doesn't really help you if you have a leak now...

I appreciate the offer. I will see what come up here first.

 

[Musicars]

I took out the line. Didn't have a drop of fluid in it which probably means I pumped a lot of air into the system I am including a picture of the hose and a close up of the blown out area. it is a bit fuzzy but you get the idea. It actually pushed the stainless steel mesh out. I was expecting a leak at the crimp.


So I called a place that makes custom hydraulic hoses and told him what I had. He says he probably can make it but needs to see it. I drive across town show the guy and he says something about not being able to do it because it would be 30 percent smaller and it was "a DOT thing". He didn't really explain it. I figured he meant that his material couldn't handle the pressures for that line.

I decide to just start hitting the junk yards but on the way I remembered a local place specializing in brake parts. They had re sleeved the original Delco master cylinder for my '65 442. Sure enough, they custom make hydraulic hoses now. This guy says no problem.

He takes me into the shop and I get to watch him cut out the old flexible section, solder new ends on, and crimp in the new section. The shop is even DOT certified. I mentioned what the first gut says and he says he can't figure it out because the first guy is also DOT certified.

So I noticed that the center section is narrower but it is also a different type of braided line. I figured as long as it functioned the same I was good with it. Then when I get home I notice the new line is marked 3.2 mm. I assume that is the inside diameter. The original hard line appears to be 3/16". I start doing the math. 3.2 mm is .126 inch which is about 1/8". 3/16" is about .188 inch. Suddenly I get what the first guy was talking about. The line is 30 percent narrower.

I called the shop that made it and they claim that 1/8" is common and there should be no problem. I think hose to wheel cylinders and calipers might be 1/8" but not so sure about what comes off the master. I'm thinking this may flow less and increase pressure in that hose. here is the picture of the new hose.


Anybody got any experience in this area?

 

[Musicars]

Thought I would post an update in case it might happen to someone else:

I installed the new repaired hose and attached it at the valve then used a syringe to squirt brake fluid into the line. My thinking was that it would allow any air near the top of the combo valve to float up above the junction where the line attached. I then bled the hose by connecting it at the master cylinder and putting a wrench at the valve connection, having my wife push the pedal, loosen the nut, hold the pedal, tighten, release the pedal, repeat. I figured since the leak was above the valve I may have limited air invasion into the valve.

The brakes seemed to work normally although I could not tell if they were a bit spongy or I was just being hypersensitive. I still had the "BRAKE" and Traction Control lights on along with a "STABILITY SYS DISABLED" and "SERVICE BRAKE SYSTEM" message on the DIC. I was positive the combo valve was stuck so I tried some hard stops but that did not work. I read that bleeding the opposite end that was closed off by the valve will sometimes work but I had no intention of doing it in the 20 degree weather.

So, as a last resort I backed into the drive way, put it in park, took a deep breath, and stomped on the brake pedal as hard as I could. The warnings all simultaneously went out and I think it is all back to normal. I still intend to track down the correct hose, if possible, but, for now, I'm good.

 

[Bombsquad85]

Sounds like you're lucky that shop was around you