some brake problems

[Nacho-RT74]

I have installed new pistons and seal kit on master cilinder, so no more interchange fluid between brake fluid deposits. I replaced the brake dist block/prop valve for a new replacement afetrmarket one that is amazing but LOOKS EXACTLY to the OEM. I think I posted link about seller on a very earlier topic. It loos works great however I'm having problems with brake when I need lot of pressure for example braking at high speed or on a quick response need. Brake warning light is of course turning on.

Last night I was bleeding the brakes with the help of my cousin since first time I tried to "bleed" the brakes by gravity I got no fluid from bleeders on an hour with bleeders opened and master cilinder cover removed.

Althought I bleed the brakes on the traditional way, still get brake light turning on and fail on brakes. Got slightly better but still.

Some good trick or advice about how to bleed on the best way possible the brakes specially with new dist block/prop valve will be great.
Thanks.

[mikepmcs]

Ignacio,
after you rebuilt the master cylinder, did you bench bleed the master cylinder?

If you didn't bleed the master cylinder, this might be your problem.

Here's what i'm talking about

http://www.misterfixit.com/brakbld1.htm

You can bleed it on the car, just take some old brake lines or a cheap kit at the parts store and install them in the original ports for the brake lines and route them directly into the master cylinder.  Fill it with fluid and pump the brakes slowly until there are no more bubbles, nice and slow about 15 times should do the trick.
Here's a picture, hope it helps.

v/r
Mike

[Nacho-RT74]

yes I have done it... not with the speciall kit, but done it out of the car just plugging the holes with fingers and leting go the brake fluid  once i got pumped the cilinders. I'll try to get the hoses and plugs kit and check that. I know a Mopar dealer does have that kit. However I never did need that before on earliers master cilinder replacements and got perfect brakes.

[MorePwr]

Can I cut in for just a second? Mike, what is that compressed gas thingy ? looks to be part of the master.

Natcho.  try bleeding the valve with the lines unhooked then hook them back up and bleed the longest lines first.. rears, right front then left front.

[Nacho-RT74]

I was thinking on bleed with lines out, using same method than the master cilinder, with plugs to bleed hooked on output prop valve and hoses to deposit.

[mikepmcs]

MorePwr,
Don't know what that is, but I have it on my 03 Chevy dually too.   
Must be some kind of assist or something.

That picture is just something I got off the web.  My charger has all the normal booster and M/C in it.

v/r
Mike

[MorePwr]

Interesting....I checked my truck, no such thing in it. so I checked Summit and found that it is a part of a hydroboost brake system that gets it's power from the power steering pump.. handy I guess, if you have low vaccume. sorry for the side track.

http://store.summitracing.com/egnsearch.asp?N=700+115+320193&D=320193

[Just 6T9 CHGR]

Those hydroboosts were popular  & expensive on the Chevy wagons of the early 90's....I used to work on them when I worked at the dealer...BIG trouble......

[Rallyecharger]

Ford has had those hydro boosts for a long time----on the SVT Mustangs,it helps for tight engine bays......
As for the bleed procedure:
1)start with a good bench bleed of the master cylinder,like the illustration given by "mikepmcs"
Using proper Dot 3 brake fluid and a clean work area.Usually the new master cylinders come with a simple brake bleed kit to use.If finances allow pick up a master brake bleed kit----trust me if you are a car guy you will get plenty of good use from it.
2)I would be careful of the aftermarket proportioning valve try to stick with OEM or repuatable brand names.More than once we have been "stung" with faulty aftermarket parts right out of the box!!
If the master cylinder is bled properly and there is no air bubbles when gravity bleeding or pressure bleeding the system then I would take a look at that proportioning valve.
---hope this helps......
    John.

[Nacho-RT74]

still same problem

and this is the prop valve I got
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=320019378265&sspagename=ADME%3AB%3AAAQ%3AUS%3A1

[GTX]

I had the same problem on mine and Page Brake, the place downtown that does brakes suggested a sticking valve or something in the prop valve?

[Nacho-RT74]

I think I'll try to rebuilt my dist block... the problem on it was the rear brakes bowl was  empting and "missed" fluid was filling the front brakes bowl, throught dist block. I think juts need to remove the rear brake out brass seat and replace the double piston O rings.

The problem will be try to get a new brass seat.