O.T. Chev Astro brakes

IA Roy · Jan 17, 2015

FIL brought out his Chevy Astro minivan. He has been loosing brake fluid. He also complains of poor or no braking. I know it is getting air in the master cylinder when the reservoir gets empty. There is a large rear brake fluid reservoir and a small front reservoir. They are both mounted on top of the master cylinder.The small front reservoir is the one that gets empty. I checked all the wheel cylinders and none of them appear to be leaking. I followed the brake lines from the rear wheels forward looking for a leak. I did not find one. I followed the front brake lines up into the master cylinder. There again I did not find a leak. There are some wet areas under the reservoirs. I assume that he spilled fluid when refilling. This vehicle does not have vacuum assist power brakes. It appears that it has hydraulic power assist provided by the power steering system. Any ideas what I am missing?

RESLLS · Jan 17, 2015

Feel the carpet where the plunger pushes the piston. Could be leaking/bypassing past the seal in cylinder inside the van.

Jeff NWOH · Jan 17, 2015

The front reservoir is for the rear brakes. Drum brakes back there I assume? Did you pull the drums and actually see the wheel cylinders? Sometimes all the brake dust and shoes will hold a lot of fluid before it actually starts dripping out somewhere.

Is the fluid from the front reservoir bypassing internally in the master cylinder into the rear reservoir?

I would just keep pumping the brakes or holding on the pedal hard, whatever you have to do to get that reservoir empty and sooner or later there will have to be a puddle somewhere on the floor.

Bob · Jan 17, 2015

The BRAKE fluid ain't gonna get to the carpet because the power steering operated Hydroboost is between the master cylinder and the firewall.

I would check the bottom of the joint between the Hydroboost and the master cylinder very closely for leaked brake fluid, though.

hoof print · Jan 17, 2015

Check to see if break fluid is running out the back of the master cylinder

IA Roy · Jan 17, 2015

Did not pull brake drums. I thought about checking under the dash but did not get to it. Next time I will check these things.
Thanks

schumy ia · Jan 17, 2015

have the same van. its most likely the rear wheel cylinders seeping. pull the drums,lift the rubbers on them to check.otherwise check the lines behind the fuel tank

farmer boy · Jan 18, 2015

Hard or soft pedal when he has a no or nearly no braking situation?

O.T. Chev Astro brakes

IA Roy

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RESLLS

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Jeff NWOH

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Bob

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hoof print

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IA Roy

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schumy ia

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farmer boy

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