Hello all

I am getting sooooo close to putting my Datsun 510 rally car on the ground and i am a little perplexed about how to bleed the brakes with a second MC installed at the hand brake. I am assuming that i will bleed the front MC first, then the front wheel brakes, then the hand brake MC, then the rear wheel brakes. Does that sound right or is there a different/better method? Thanks

Mike G

The best bleed technique I have found: Put a hose on a rear bleeder and loop it up then down into a bottle. Open the bleeder and leave open the whole time. Pull the hydraulic handbrake and hold light pressure on it and pump the brake pedal letting the handle return with pedal pumps. Repeat 5 -10 cycles, keeping fluid in the master. Repeat at the other rear wheel.

Cool thanks for the info I should be bleeding the lines next weekend.

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phlat65
The best bleed technique I have found: Put a hose on a rear bleeder and loop it up then down into a bottle. Open the bleeder and leave open the whole time. Pull the hydraulic handbrake and hold light pressure on it and pump the brake pedal letting the handle return with pedal pumps. Repeat 5 -10 cycles, keeping fluid in the master. Repeat at the other rear wheel.

This is the way I found best as well. Holding the handle down while pumping the foot brake blows fluid through the headspace in the handbrake master as well as the working area. Being lazy, I just use a bungie to hold the handbrake lever back until bleeding is done.

Wait a second, is this on a twin master balance bar system? If not then just bleed it as if you were just bleeding the rear brakes. Maybe pump the handbrake a couple of times to check for firmness but thats about it.

Is it different on a twin master system? I just bled like normal even with dual masters, didn't even touch the handbrake...

I never messed with the handbrake either when I put the BMW together. No brake issues at all.

Dave

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NoCoast
Is it different on a twin master system? I just bled like normal even with dual masters, didn't even touch the handbrake...

Yes, you dont really touch the handbrake, the thing with the twin masters is that you should bleed the front and rear at the same time to prevent the balance bar from 'cocking' and possibly bending.

Ahh. That makes sense. Well, guess I got lucky with my high dollar CompBrake balance bar. Or maybe it did bend and that's why it took a wrench to get it adjusted... Pretty sure that was more due to the brake fluid and dust that it's caked on.

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NoCoast
Ahh. That makes sense. Well, guess I got lucky with my high dollar CompBrake balance bar. Or maybe it did bend and that's why it took a wrench to get it adjusted... Pretty sure that was more due to the brake fluid and dust that it's caked on.

You'd be surprised on easy they bend. Normally the redneck round track racers use are the ones running the cheap stuff form wilwood and coleman etc, and when they crash its normally ON the brakes and that G force from the impact is enought to bend that shit to hell and back. Just think about it: big'ol country boy moonshine drinkin and chew spittin gits himself in a spin and dun slams them brakes with all he's got just before slamming the wall. Pedal pressure, 150lbs before impact, after a MILD -4G impact easy 300lbs. So 300lbs x the pedal ratio - about 6:1, it equates to 1800lbs on the 3/8"s diameter balance bar.

-4g kick to the nut sack!

Hello all...again

Tonight I started the bleeding process (brakes not blood thankfully) I had my daughter doing pedal duty while i ran around and performed the obligatory bleeding at each corner starting with the farthest from the M/C. I decided to pull the hand brake all the way back during this process. I asked my daughter every time i opened the bleed screw if she felt the pedal fall she told me know (only on the rear brakes) the front she could feel it. I then noticed that the hand brake was in the forward position. Hmmmmm i thought ok lets try it now with the hand brake in that position. She could feel it this time and all the brakes were void of any air. I had my daughter pump the hand brake a few times and I instantly noticed the reservoir spilling over the top. So after all that what have i done wrong here is a pic to help with my setup.



The line coming from the front of the car is going to the M/C and the line from the back is going to the rear brakes. I also noticed that if i pulled the hand brake back and pushed on the brake pedal the hand brake would try to go forward. In its current state If I pump the hand brake it is easy to pull then if i pump the foot pedal it is easy for about 2 pumps then gets stiff again. I looked on the hand brake cyl. for a flow chart but I did not see any. Could i have the cyl. plumbed wrong? Thanks for any help you can give me.



Edited 1 time(s). Last edit at 11/08/2011 07:16PM by BlackWidow.

well everybody says I'm all opinionated and know-it-all and a generally sociopathic dooood and everything so I'm loathe to criticize so I'll turn over agnu leaf and I won't.
Nice install.
I will meekly point out however that I almost always try and plumb the hard line from the footbrake master INTO the INLET of the handbrake master, and it usually seems to work better most of the time.
And bleeding goes a lot better-er.

But hey, who the fuck am I to say anything? There's really no right and wrong and like everybody has their own like reality, man, so you want to do it that way, then cool, doood. Maybe they switched the inlet to where the outlet has always been, maybe that one master was like unique, maybe cosmic raaaaaays like fried a synapse in the brain of the dood machining it!
Maybe this drawing is like all fucked up:


More guys do it that way first than the silly drawing.
They should pay attention to customers, I mean so many do it the way you did, they ought change it.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
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is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 11/08/2011 09:36PM by john vanlandingham.

You have the lines backwards on the master. On those Girling type masters the feed port in the front one. Just switch them around and you'll be good.

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john vanlandingham
More guys do it that way first than the silly drawing.
They should pay attention to customers, I mean so many do it the way you did, they ought change it.

They already do homie. All the good modern (less than 40yo) master cylinders dont have the fluid flowing in reverse like those. Look at the Tiltons, AP, Alcon, Brembo. If the piston builds pressure towards the front then why have the feed port at the front and the outlet at the back. No point in having crazy internal reversing of the fluid creating all kinds of hysteresis and impossible to bule print the travel to cut off.