Problem with new Master Cylinder.......

[ChiefRocka]

Ok, I have my truck running really well now, with the updated engine.

I'm having an issue with getting the brakes to bleed. I was told that the 'REAR' port on the master feed the front brakes, and the 'FRONT' off the master feed the rear brakes.

Now, I purchased a NEW drum/drum master for a '67 Impala...it bolted up really nice.

I went to bleed the brakes today...the rear brakes have mega-pressure, but I can't get nothing from the front....barely pours out.

Now someone here (I forgot who) told me the the front res. feeds the rear port and vica-versa......As I bleed the rear brakes, the front res. drains (??)

Could this master be different or bad ??

This is all I need to get the 'Chief' on the road !!!

Any ideas....I know this should be a no-brainer, but....'what the f##k !!!'



John

[ChiefRocka]

For those who haven't seen my build this is the Master and the how the ports were hooked up....

[Pistonman]

Did you bench bleed it?

[slepysal]

i think the ports may be wrong If I rrecall the small resivour feeds the rear , the larger onr the front. try this link

http://www.classicperform.com/TechBo...oubleshoot.htm

[62 short step]

I thought the port close to the fire wall was for the rear brakes?

[ChiefRocka]

Originally Posted by Pistonman

Did you bench bleed it?

OH YA...I bench bled it for days !!! It took a while, but I got every last little bubble out of the darn thing !!!

[ChiefRocka]

Originally Posted by slepysal

i think the ports may be wrong If I rrecall the small resivour feeds the rear , the larger onr the front. try this link

http://www.classicperform.com/TechBo...oubleshoot.htm

I will check it out. However, on this Impala master the resivours are the same size. I thought the larger port (front) was the front brakes...RICH told me the front brakes were the rear (?!?!?)

It sucks, because I had my lines bent perfect, now I might have to switch them...

JOhn

[ChiefRocka]

Also...there shouldn't be a need for a prop. valve with a drum/drum set-up, right ??

[Ivan D.]

Chief, yer friend Rich is correct, the larger port (usually front) with the smaller reservoir usually feeds the rear brakes, and the smaller port with the bigger reservoir usually feeds the front - has to do something with different pressures required, or something along that line. You have the same size of reservoirs cause yer brakes are drum/drum so they require about the same amount of fluid to go in all of them, however the pressure difference requirement is still there. So hook yer front brakes to the smaller port, the rears to the bigger one, and try to bleed again.

Another thing to look at are the flexible brake hoses - with age those tend to disintegrate and collapse internally, thus blocking fluid from going in and out.

[Dadsredwagon]

any pics of your 71 nova ss I own a 72 model....

[wild one]

Thought this might help, I found this some time ago on EVILBAY - Good info and explanation. The seller is http://myworld.ebay.com/pirate-jack-asheville-nc just look up any proportioning valve that they list and scroll down, lots of other interesting stuff.

Are the brass fittings on the master cylinder adapters or one way valves? Possibly residual valves?

DRUM BRAKES FRONT AND REAR WITH MASTER ON FIREWALL OR UNDER FLOOR

* drum/drum, firewall or under floor

Drum brakes require a 10 lb. residual pressure (RPV10) to counteract the spring tension in the drum system which tends to pull the shoes away from the drums. This will give you a longer pedal travel and "spongy" brakes. The residual valve holds a pressure keeping the shoes near the drums giving a higher firmer pedal. Also required a metering valve (PVM) to the front (the metering valve prevents nose dive).

[ChiefRocka]

Originally Posted by Ivan D.

Chief, yer friend Rich is correct, the larger port (usually front) with the smaller reservoir usually feeds the rear brakes, and the smaller port with the bigger reservoir usually feeds the front - has to do something with different pressures required, or something along that line. You have the same size of reservoirs cause yer brakes are drum/drum so they require about the same amount of fluid to go in all of them, however the pressure difference requirement is still there. So hook yer front brakes to the smaller port, the rears to the bigger one, and try to bleed again.

Another thing to look at are the flexible brake hoses - with age those tend to disintegrate and collapse internally, thus blocking fluid from going in and out.

THATS WHAT MY BUDDY TOLD ME.....MY BRAKE HOSES ARE ALL NEW...

Originally Posted by Dadsredwagon

any pics of your 71 nova ss I own a 72 model....

NO PICS OF THE NOVA...TRYING TO GET MY BRAKES GOING....

Originally Posted by wild one

Thought this might help, I found this some time ago on EVILBAY - Good info and explanation. The seller is http://myworld.ebay.com/pirate-jack-asheville-nc just look up any proportioning valve that they list and scroll down, lots of other interesting stuff.

Are the brass fittings on the master cylinder adapters or one way valves? Possibly residual valves?



DRUM BRAKES FRONT AND REAR WITH MASTER ON FIREWALL OR UNDER FLOOR

* drum/drum, firewall or under floor

Drum brakes require a 10 lb. residual pressure (RPV10) to counteract the spring tension in the drum system which tends to pull the shoes away from the drums. This will give you a longer pedal travel and "spongy" brakes. The residual valve holds a pressure keeping the shoes near the drums giving a higher firmer pedal. Also required a metering valve (PVM) to the front (the metering valve prevents nose dive).

NO THOSE ARE ADAPTER FITTINGS....

OK ACCORDING TO THIS PICTURE...THE REAR PORT GOES TO THE REAR BRAKES (???)

I SHOULDN'T NEED ANY OTHER VALVE FOR THIS SET-UP..SHOULD I ??

I AM LIKE FRUSTRATED RIGHT NOW.......


SHOULD I TRY SWAPPING THE LINES OR WHAT ??

JOHN

[ChiefRocka]

ONE MORE THING I FORGOT TO MENTION

THE REAR PORT DRAINS THE REAR RESERVOIR

THE FRONT PORT DRAINS THE FRONT RESERVOIR.....

John

[slepysal]

Yea John no valve is need ed for the drum/ drum. Any progress ?

[62 short step]

I always assumed the rear port closet to the fire wall was always for the rear brakes. I would try swapping to eliminate that. My 2 cents.

[ChiefRocka]

Well I just home..and even before logging on I tryed the swap..and it works now.....

Now my lines look like s#it because I had them bent nicely to the ports...I might need to re-bend a new line sometime.

A drum master is supposed to have checks, but not sure if this one did or not. I didn't check before installing the lines....and I'm not going to pull them right now to check either.

But at least it's work'n !!!!

John

[62 short step]

Cool, glad you got it solved!! Now you can go burn some rubber!!!

[ChiefRocka]

Originally Posted by 62 short step

Cool, glad you got it solved!! Now you can go burn some rubber!!!

[1966gmc]

So the front brakes are the rear port on this set up. Im a bit confused lol