Chevy & GMC Vans

This is a Previous post from the archives made by Socali V8 I figured since I had to search for it might as well repost it:


Bleeding your hydraulic brake system is always a real pain in the a$$, especially if you have modified your system by fitting a rear disc set-up, or larger calipers, adjustable proportioning valve, etc, etc, etc........



Here is a simple tool that was made at my autoshop years ago, although you can buy them as a proper brake bleeding tool, you can make one for much cheaper.



It consists of a plastic sealed bottle/ tub which is 3/4 full with new brake fluid that can be pumped up and pressurised with a simple handle (insecticide bug sprayer). A pressure guage (5-8psi pressure is used) plus an adapter which screws onto, or fits over, the brake master cylinder.



You can buy adapters that with a chain will clamp down onto your round filler neck, or in the case of Chevy master cylinders a larger rectangular adapter is needed.



This clamps ontop of the master with a simple lightweight chain, and the handle is pumped up exerting 8psi onto the hydraulic system while filling the master at the same time.

If you have replaced the master cylinder, you should begin by bleeding those ports first, simply crack them open 1/2 a turn and let all the bubbles flow out (@ 8psi pressure) until you see fluid only.

Thanks for posting these pics up! I made it a sticky too.

Cool, I went looking for these, but never found them. This brakebleeder works fantastic, one man brake bleeding that bleeds all air out the the wheels even through all the ABS components.

At my work we pressure bleed out customers brake systems everyday, it gives them a firmer brake pedal and makes all the brake components last longer. If your brake fluid is darker than light brown it is contaminated, and this tool will improve pedal feel.

My own car is 21 years old (`87 Merkur XR4TI ) and all the brake components are original and work perfect, I put this down to brake fluid flushing.

The large plate is actually for a Suburban that has one large master cyl reservoir, I have smaller square and round plates for other cars. You can build this for about $25 and a tool definately worth having, ( for ease of use and to save your patience ) even if you only use it once.

Seems like the original post lost a last sentence, so let me add it here.


If you have replaced the master cylinder, you should begin by bleeding those ports first, simply crack them open 1/2 a turn and let all the bubbles flow out (@ 8psi pressure) until you see fluid only.

Then begining with the wheel furthest away from the master cylinder and moving to the closest, connect a rubber tube onto the loosened bleed nipple into a clear jar. Close the bleed nipple when the fluid is coming out is clear and yellow.

Nice one Darren.

Got a question for you all here that may help me.

I use a phoenix injector to push fluid through the lines



and i have just changed the front to rear 1/4" line from the ABS modulator to just above the back axle. Just bleed the brakes out and we are done. Easy eh?.........................no...............







I cannot get any fluid through from the master cylinder to even the join under the drivers seat section of the floor. I can inject fluid to come out of the ABS pump but it will not emerge from the pipe exiting from that. And the pipe is definetly clear. Even mityvac on one side pulling, and the phoenix injector pushing, I can get no fluid flow. I know I have done this before on this van when Darren got me a replacement prop valve, but this time I cannot do it.

Does the ABS have a restriction in it? Any advice from you guys? Anyone come across this before?

Andy.

Hey Andy,
I hate to be the one to tell you this, but brake fluid attracts moisture.
Copper corrodes on contact with water.
This corrosion will contaminate your entire braking system.
Use steel or stainless steel for brake lines. [-X
Peter

The copper is not a great idea when running brake lines. I bought a 31 Model A Coupe streetrod years ago that was a partial build. The guy had used copper for the lines. What you'll find is, the lines will expand when applying the brakes. This much line pressure and copper will give you a mushy feel in the pedal and if there are any weak areas in the tubing, you'll blow a line. Also may have issues sooner or later with rocks or anything else flying up while your running down the road and hitting the line causing a puncture.

Kabey's Van wrote:Hey Andy,
I hate to be the one to tell you this, but brake fluid attracts moisture.
Copper corrodes on contact with water.
This corrosion will contaminate your entire braking system.
Use steel or stainless steel for brake lines. [-X
Peter

Hi Peter.
Thanks for the answer. Here in the Uk we have used this pipe for decades now and no problems. Every garage and shop uses it and has done for years and years. I have worked on cars for the last 30 years and always had highly efficient braking systems with no contamination beyond the norm.
Still doesn't explain the no fluid flow though

Andy.

Thanks for the answer. Here in the Uk we have used this pipe for decades now and no problems. Every garage and shop uses it and has done for years and years. I have worked on cars for the last 30 years and always had highly efficient braking systems with no contamination beyond the norm.

\
Oh, it'll work for sure but not the best or safest material to use for lines. You will get that mushy feeling in the pedal sooner or later. In fact, after you've run those lines for some time, you can apply the brake and actually see the tubing expand from the pressure. Good luck and no idea on the blockage. One of those strange car things that happens more often than not.

Some styles of proportioning valves have a pin at one end (that maybe under a rubber grommet) that needs to be pulled out when bleeding. I`m not sure if Chevys are like this though..... ?

My Astro has a button on the rear of the proportioning valve like Darren is talking about. Has to be pulled out while bleeding.

OK, then Chevy`s do have that style....

wow ,,copper wouldn't last long here

Guys, I bet that tubing that Andy is using is not exactly copper; I believe that it's a product called Cunifer. Click here

He doesn't say whether it's copper or not, but he does say they have been using it for 30 years or more so I am guessing it's copper.
A 1932 Whippet my dad owned for years had copper and brass everthing but it only saw the nice days out on the road. As far as regular use, copper would only last a couple of years out here and then would just fall to pieces. The salty air, the humidity and the winters would take a very fast toll on that stuff.

Peter