Master Cylinder??

[uspowers]

Greetings,

 

2000 Outback is exhibiting symptoms of a bad master cylinder. No braking power, pedal hitting floor, no external leaks.

 

I bled brakes with a mity vac bleeder. I pulled 4 x 4oz. cups of fluid through the right rear bleeder and never got rid of air bubbles.

 

Could they be coming from the master cylinder?

 

Thanks

 

Bob

[Fairtax4me]

Vacuum bleeders generally don't make a perfect seal at the bleed screw and you will continuously see bubbles no matter how long you bleed. If the fluid was coming out clean, then it should be good.

 

Did you drive the car after bleeding? Pedal still sinking?

[idosubaru]

i've seen master cylinders fail that kept introducing bubbles into the brake fluid. sounds like MC to me but hate to throw parts, so whatever tests you can do or suggestions made are a good idea.

[Rooster2]

I too, would think a bad MC, particularly since the brake pedal keeps sinking to the floor. I don't think a new one is that costly, so you are not out much money if you install one yourself. It will give you the opportunity to use your bleeder tool again.

[uspowers]

Thanks for the responses.

 

I can get a rebuilt MC for $40.00.

I'll give it a try.

The bubbles at the rear bleeder was throwing me.

Bob

[uspowers]

Rebuilt MC installed no improvement.

Thought air in ABS system.

Brought to dealer. Dealer says new discs installed with old pads all aftermarket caused glazing.

 

Pad and rotor replacement $900.00.

 

I said thank you and I'll pay for the diagnosis.

 

I'm open to suggestions. The pads and rotors are all less than 20K miles.

 

Bob

[lmdew]

Try pressure bleeding the brakes, you can move a quart or two through in no time.

 

Home made version:

 

http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/bleeder/index.htm

 

Note the small yellow caps of the 96-99 Subaru's do not seal very well, so I use the one from the Motive Flow Brake bleeding system.

 

Search Power Brake Bleeder and looks for JEGS.

[idosubaru]

i just had the same thing happen - folks are starting to suggest that rebuilt MC's aren't near 100% so it's likely it's the rebuilt MC. i haven't gotten around to replacing it yet, but it's really annoying trying to figure this out.

 

the dealer was definitely looking for easy money, they only quoted $900 because $1,000 would be grand theft :lol: they deserve a solid kick to the groin for that. volunteers anyone?

[Rooster2]

i just had the same thing happen - folks are starting to suggest that rebuilt MC's aren't near 100% so it's likely it's the rebuilt MC. i haven't gotten around to replacing it yet, but it's really annoying trying to figure this out.

 

the dealer was definitely looking for easy money, they only quoted $900 because $1,000 would be grand theft :lol: they deserve a solid kick to the groin for that. volunteers anyone?

 

I would have laughed loudly in the guy's face at a $900 quote, then asked him to quit kidding around, and give me an honest quote!

[Fairtax4me]

I assume you also tried bleeding the old fashioned way?

 

$900 sounds about right for pads and rotors on all 4 plus 2.5 labor per axle at dealer prices. If that's a quote for just one axle I'd file a complaint with the BBB.

[idosubaru]

$900 sounds about right.

the main issue is that pads and rotors won't fix a brake pedal going to the floor. it is also extremely odd to need all new front and rear pads and rotors at one time. he said nothing about vibrating or shaking so his rotors are likely fine, or it would be very odd for all of them to need replacing. they should be turned at most, not replaced. i know you're aware of all that anyway, but i think it's the poor diagnosis, not the cost that is alarming.....well the cost is crazy too!

[uspowers]

After further inspection found both front caliper bottom sliders (the ones with the rubber tips) seized up.

 

Cleaned and lubed and brakes better but still will not lock up.

 

Thinking of replacing both bottom slider with top slider pins (without rubber tips).

 

Also will replace pads, as they appear to have an angle worn into them from the uneven pressure of the calaiper, due to sliders not moving.

 

I'll post when done.

 

Thanks

Bob

[idosubaru]

they sell kits for replacing all the rubber boots and pins. nice to take them with you though and make sure as subaru has a LOT of different caliper set ups, it's really annoying and you get the wrong parts often.

 

might want to flush your fluid too - probably never been done and it's 10 years old. some fresh fluid might make a world of difference. fluid changes extend the life of braking system components too.

[Fairtax4me]

I bled brakes with a mity vac bleeder. I pulled 4 x 4oz. cups of fluid through the right rear bleeder and never got rid of air bubbles.

 

 

 

Also will replace pads, as they appear to have an angle worn into them from the uneven pressure of the calaiper, due to sliders not moving.

That would certainly cause a loss of braking power. It can also damage the calipers if left that way so new pads are definitely the way to go. As Gary already said a whole new caliper hardware kit would be a good investment.

[uspowers]

Job complete!

 

Replaced bottom sliders with top slider pins, lubed and installed new pads.

 

Stops great! pedal still quite low, but as long as braking well, I'll take it.

 

Thanks for all input.

Bob