Leaky brake master cyl - advice needed

kevmif · Post by **kevmif** » Mon Oct 19, 2009 11:06 am

So I tried to do the right thing and replace my dodgy brake hoses - anyhow, apparently with Subarus your not supposed to bleed the brakes like you do older cars (my old man taught me that you pump the brakes several times, hold your foot flat down, have someone release the valve and tighten it again then let the brake pedal come back up and repeat til no air bubbles). So I've since found out that this process will screw your master cylinder. (Would have been nice for the Gregorys manual to detail the correct process).

So I am driving around with a leaky cylinder which according to the man at Mr Brakes could let go at any time. He refuses to fit a second hand cylinder however he will supply and fit a new one for $320. So now I am faced with three options:

i) Pay the money and have Mr Brakes fix it. (reco'ing the existing one is an option too, but its at least $120, likely more).
ii) Get a second hand master cyl from the wreckers and attempt to learn the correct process for fitting it and bleeding the brakes.
iii) Just top up the fluid every few days,

Now, normally I would go with option 2. However since my Toyota was rear ended a few weeks ago and written off, I am depending on the Brumby to get me everywhere - so having the car off the road for anymore then a day is not an option and the likelyhood of me screwing it up again is high.

Option 3 is quite attractive at present however the man from Mr Brakes made it seem as if the likelyhood of the cylinder letting go completely at any given point was high. Dunno if this is true or not, but I do kind of like my brakes to work when I press the pedal.....

Very frustrated and pissed off at the moment, so any good advice that could be offered conveyed in a way that an idiot like me could understand would be much appreciated. Someone previously put up photos and an explanation in a previous thread however I didn't fully understand and didn't want to sound like an idiot asking for further clarification on what should have been understandable and I just ended up going about things the way my old man recommended. Guess that was a stupid (and expensive) mistake.

Thanks.

GOD · Post by **GOD** » Mon Oct 19, 2009 11:16 am

What's different about Subaru master cylinders? I've bled mine the way you describe.

Where is your master cylinder leaking from? The brake fluid reservoir on my L has been slowly leaking for ages, but it doesn't really bother me because the high-pressure side is fine.

Best option is probably to get it replaced with a newie or reconditioned. Chances are a second hand one from the wreckers will need an overhaul before too long.

Dane.

T'subaru · Post by **T'subaru** » Mon Oct 19, 2009 11:31 am

I have on all my vehicles including my subi's bleed the brake system with a vaccum hose and a glass jar. Start with the furthest cyl away from your master ( based on pluming ) cylinder. Install wrench on zerk, push on tight fitting vaccum hose and submerg other end of hose in clean fluid in a clear jar. crack fitting and slowly cycle pedal slowly until no more air comes out. tighten zirk and
keep working each cyl from furthest to closet to the master ( you can put droplight behind jar and work pedal by hand as you watch for bubbles) Dont forget to check fluid level in master resiv frequently as you bleed this way. this works extremely well when replacing old dirty fluid too, I use a small turkey baster to pull as much of the dirty fluid from the resiv and fill with clean before starting, just keep bleeding until clean fluid is all your getting. keeping hose submerged while bleeding this way is critical, as you push the pedal to the floor you force out any air, and when the pedal returns to top it pulls fluid up instead of air.

kevmif · Post by **kevmif** » Mon Oct 19, 2009 11:42 am

GOD wrote:What's different about Subaru master cylinders? I've bled mine the way you describe.

Where is your master cylinder leaking from?
Dane.

The guy from Mr Brakes and another member here both mentioned that the pedal should not be pushed all the way down, but I have bled brakes on other cars before and that is the first I have heard of it. It looks to be leaking from where it connects to the brake booster.

GOD · Post by **GOD** » Mon Oct 19, 2009 12:17 pm

kevmif wrote:The guy from Mr Brakes and another member here both mentioned that the pedal should not be pushed all the way down, but I have bled brakes on other cars before and that is the first I have heard of it. It looks to be leaking from where it connects to the brake booster.

Ah yes, now that you mention it I have head that. I think that's to do with collecting any crud that may be sitting at the end of the cylinder when you push the pedal to the floor, then on the way back up the crud can damage seals or the cylinder bore. Applies equally to all cars.

Yours sounds like a bad leak

.

Dane.

AndrewT · Post by **AndrewT** » Mon Oct 19, 2009 2:03 pm

If your keen then strip it down, hone the cylinder and put a re-seal kit through (i think these cost like 15 bucks). Otherwise just goto a brake place and get it done by them. Lots of places keep exchange-stock on the shelt so it's a quick changeover. Don't take a second chance with brakes.

AlpineRaven · Post by **AlpineRaven** » Mon Oct 19, 2009 8:24 pm

You can rebuild the kit yourself like what AndrewT said.

As the way you described about bleeding the brakes is same what I've always done with previous cars that I've had.
Cheers
AP

phillatdarwin · Post by **phillatdarwin** » Mon Oct 19, 2009 11:07 pm

if u are only replacing the master bleed the master up on the bench before u fit it remove the old one put the new one in do the pipes up pump the brake a thro times and just bleed it at the master wear the pipes go in with the brake pedal down as with presser in the line most of the time the bit of air that was in the the top of the line will come out at the master to brake line fitting .