Brake Master cylinder replacement?

AaronA · Post by **AaronA** » 07 Apr 2011, 05:15

I have a 2001 V70 T with 108K miles. When I come to a stop, the brake pedal feels a little spongy, then when I'm sitting at the stop with my foot on the brake, the pedal gradually keeps going down. The reservoir is still full so I am assuming it's the master cylinder. I'm wondering if someone can confirm the diagnosis or ideas of something else I should check?

The repair looks pretty straightforward - remove fluid from reservoir, disconnect brake lines, remove bolts and slide master cylinder out. Transfer reservoir to new one then reinstall. Bleed brakes. Am I missing anything? Do I need to remove the upper cross support? Do I need to prime the reservoir before I install it?

Anyone have experience with aftermarket master cylinders? I was going to order from IPD, but any hints would be helpful.

Thanks!
Aaron

Post by **jblackburn** » 07 Apr 2011, 07:56

Yep, that's a master cylinder!

If brake fluid were low I'd suggest looking for a leak in a line/caliper first, but it doesn't sound like that is your problem.

When bleeding with the new master cylinder, DO NOT let the pedal sink to the floor, or you'll be right back in the same situation again.

jda2000 · Post by **jda2000** » 07 Apr 2011, 08:26

is there a hiss by the brake pedal?
Brake booster failure is high in these cars.

Post by **jblackburn** » 07 Apr 2011, 08:31

Booster still should maintain pedal pressure (not sink to the floor); it will just be harder to stop.

AaronA · Post by **AaronA** » 07 Apr 2011, 08:36

Thanks for the confirmation. I also would assume that if it was the booster, the pedal would just get harder to push.

Any experience with aftermarket Master cylinders?