Brake issues...

[Mefirst]

Ive rebuilt the brake system in my ride. Problem is that what ever I do I cant get a firm brake pedal. Ive bled the brakes like a million times and have probably flushed through the system with 3qrts of brake fluid...

Weird part is that when I took the car to the Car Inspection and did the brake test the brakes do work OK even though the pedal feels so weird..

I'm using DOT 5 brake fluid. (Can this be the reason??? Should I change back to DOT 3???)
MC is a 1971 cylinder. Tried a 1970 MC but for some weird reason the pedal travel was to long so it blocked out the rear brakes..
Al brake parts are new
Wilwood prop. valve
I use braided brake lines in the front. I still have the short rubber hose in the rear? Could it be "ballooning" due to brake pressure??? Maby I should change it out to a braided line???

/Tom

[mikepmcs]

Tom, forgive me for asking and i'm sure it's been said. Is this a power brake system??
Just want to make sure all bases are covered.

[Mefirst]

  Mike

No power brakes

/Tom

[mikepmcs]

K, I thought not but just had to make sure for my own piece of mind.
I don't know the answer about the fluid.
How about the valve out back.  The residual pressure valve.  You have one of them in there? 

http://www.wilwood.com/Products/006-MasterCylinders/010-RPV/index.asp

[Mefirst]

I didint even know there excisted a residual pressure valve.. But -No, I dont have a valve like that.

The weird part is that the system has worked well before with out any issues. Only difference now is that I have rebuilt the rear brakes, changed the front brake lines to braided, use DOT 5 fluid and had to buy a new MC cause the old one took a dump...

[mikepmcs]

One last thing, you did bench bleed the master first before the install?
That could cause the problem you are having.  If that isn't it, then possibly another bad M/C.

Check this article out, it explains it better than I can.

http://www.tegger.com/hondafaq/mastercylinderreplace/benchbleeding.html

[Mefirst]

Yeah, I did bench bleed the MC. I have also though about the possibility that the new MC is bad...

[Charger-Bodie]

Sounds like you need to adjust the shoes... You will get a funny pedal if the shoes need to travel a little bit before hitting the drums.

[Mefirst]

I have adjusted the rear brake shoes (drums in the back, discs in the front) so they lightly touch the drums, I can feel that they drag just a little bit..

The pedal feel did also get better when I turned the prop. valve so its just a fraction open to the rear brakes, if I close it more, I loose the rear brakes..

So...

1. Still got some air trapped in the system eventhough I have bled the brakes many times.

2. The short rubber brake hose, that connects to the split on top of the rear axel, "balloons" cause of pressure. (This problem occurs many times when one changes the front brake lines on a motorcycle to braided ones, but but not the rear, so these are still rubber hoses and they "balloon" because of the raised pressure in the system.)

3. The pin that goes between the brake pedal and MC is to short? Though it has worked before with out problems with the old MC that is exactly the same as the new one.

4. The use of DOT 5 brake fluid. (The DOT 3 fluid seems to be thicker) The MC "gaskets" are not holding the pressure cause of the thinner fluid..

/Tom

[Mefirst]

Update 19/5

Put in a 10 Psi Residual pressure valve in the rear brake line -Now the pedal feels really good and firm..

-Thanks Mike for the tip!!!

/Tom

[mikepmcs]

Tom,
got your PM.. Your inbox is full so I couldn't respond.

That's awesome!!!!

Mike