Chevy & GMC Vans

I saw copper colored (don`t know if it was genuine copper) brake lines on a 1990 Volvo the other day.

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

You are quite right SafariRob, it is kunifer tubing. back in the day it was called kunifer 10. In regards to the corossion resistance, it has to be protected like anything else.

Andy.

Thank you gentlemen who replied and offered advice.

Following advice given, I opened up the right rear bleed valve, topped up the master ctlinder and waited and waited ...............................................................



1, 2, 3 hours and nothing, but the level had dropped in the reservoir.

So, I attached my mityvac vacuum pump, pumped the handle a few times and got it to 26" Hg! Never got the pump to do that before.




That is one heck of a mighty pull I can tell ya! 30 minutes or so later and we have fluid flowing. A couple of careful slow presses of the pedal with the vacuum still there, and we have good flow. Repeat on the other side and we have fluid there as well. And air free!

So, my advice to all is pour the fluid in and wait....patiently.....

Now I did fluid dynamics as part of my maths degree at university, but this is an interesting project. As cudapaul says (by the way thanks for the offer of looking in the shop manual) the restriction is in the ABS module. But why did the pressure bleeder not have much effect? Or even the vacuum pump at the same time? Well my lecturer wouldn't like this, but, the best way I can describe this is to compare it to thousands of people in a big room trying to get through a small door in a stampede and all pushing hard. Nobody gets through. But if they all go down to walking pace and not push, they will get through a lot quicker and easier Not very scientific I know but a good analogy I think!!

Anyway, the job is done and the van is back on the streets.


Andy.

Thanks for telling us the outcome Andy, glad to hear it worked out.

water will not hurt the copper - all the road grim might - think about water lines in your houses

The copper water lines in your home are protected by the home and they're grounded. If they weren't they would tarnish and corrode just like a penny on a sidewalk.

TheChopFather wrote:
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........

Hi guys, great advice. I have heard that there is a way to make your ABS pump fluid in order to bleed the lines. Someone mentioned that the ABS system can be tricked or activated from the computer or a jumper in the wire. This is what the dealership mechanics do, but I think they have something that plugs in to the computer.
Has anyone heard of such a trick? Can this be researched?

I am now in the middle of replacing all of my steel brake lines.
2000 Astro, 143k miles; Pennsylvania.