How to fix Geo Master cylinder and power booster brakes

JDKOSKELA

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2012 ALL OTHER MAKES ALL OTHER MODELS
70,000 MILES

I recently just finished building a trike but am having troubles with the brakes. They work but take much too long to slow down/stop suddenly. They don't seem to be locking. I tried both the front and rear port of the master cylinder which made no difference. Should I try bleeding the brakes again? If you have any ideas I'd appreciate it.

If you need specs:
Rear end: Model 200 Nissan
Brakes: Geo master cylinder and power booster

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Thursday, December 29th, 2011 AT 6:48 PM

14 Replies

FIXITMR

MECHANIC
9,990 POSTS

Is it disc brakes?

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Thursday, December 29th, 2011 AT 6:51 PM

CJ MEDEVAC

MECHANIC
11,004 POSTS

USING ONLY ONE PORT OF THE MASTER CYLINDER?

BOTH SIDES FULL OF FLUID?

IS THE OTHER PLUGGED OFF?

IF PLUGGED, MAYBE THAT PORT IS BUILDING PRESSURE INSTANTLY--AND NOT ALLOWING THE PISTON TO TRAVEL FURTHER TO MOVE FLUID IN THE OTHER RESERVOIR

JUST THROWING CRAP---I'VE NEVER USED ONLY HALF OF A MASTER CYLINDER

TIE 'EM/ TEE 'EM TOGETHER?

PUMP ONE SIDE DRY AND LEAVE IT UNPLUGGED?

USE A SINGLE RESERVOIR MASTER CYLINDER AS MY 1946 WILLYS JEEP USES?

MAYBE SOMETHING I SUGGESTED WILL HELP OR SPARK AN IDEA

THE MEDIC

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Thursday, December 29th, 2011 AT 9:13 PM

FIXITMR

MECHANIC
9,990 POSTS

Tee them together was a thought I also had. Got enough vaccum to booster? Does pedal feel right? Aint no proportioning valve inline some where? Did you actually look at brake parts in wheels?

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Thursday, December 29th, 2011 AT 10:09 PM

JDKOSKELA

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5 POSTS

Yes they are disc brakes and one side is plugged and the other runs to the rear brakes. No proportioning valve inline.

How do you test vacuum to the booster, I just have vacuum in hose.

Teeing them together sounds like a good idea, do you think it would work without a proportioning valve?
Yes and brakes look good, they just take a long time to slow down and the pedal pushes in further than expected.

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Friday, December 30th, 2011 AT 2:03 AM

CADIEMAN

MECHANIC
3,544 POSTS

Remove the hose on the booster check for vacuum. If the front is running on handle bar master. Youll need to install a 1 port master that has the same hook ups and specs. As oe. If you want the booster. It has to have everything that was on the orignal sys.

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Friday, December 30th, 2011 AT 2:27 AM

FIXITMR

MECHANIC
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That's what I was assuming original handelbar front brakes?

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Friday, December 30th, 2011 AT 5:55 AM

JDKOSKELA

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Yes the original handlebars front brakes are fine.

If the master cylinder is lower than the calipers, would that make a difference in the movement of fluid and brake performance?

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Friday, December 30th, 2011 AT 6:48 PM

FIXITMR

MECHANIC
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Interesting question? I would guess NO.

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Friday, December 30th, 2011 AT 8:59 PM

JDKOSKELA

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Thank you all for your responses I've been trying all the advice you've given me with no luck so far but if I have any more questions I'll post them here. Hope you like the trike I'll add a few more pictures for you.

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Saturday, December 31st, 2011 AT 12:33 AM

FIXITMR

MECHANIC
9,990 POSTS

Will teeing together give twice the hydraulic pressure? Is caliper piston size relavent to master cylinder bore diameter? Dos booster feel like it is functioning ok?

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Saturday, December 31st, 2011 AT 1:13 AM

CADIEMAN