1999 V70 Spongy brake pedal

DavidsVolvo · Post by **DavidsVolvo** » 09 Sep 2014, 12:25

The brake pedal does not feel the same anymore. it travels further and requires more force to stop the car. Its as if the car had manual brakes like some of the cars did in the 1960s. The pads and rotors are all newish, there is no leaking fluid and the calipers have been bled.

What do I need to look at for the vacuum brake booster or other components that would cause loss of power assist?

Post by **850 LPT** » 09 Sep 2014, 13:21

This sounds to me as if you have air in the lines. How did you bleed the brake system?
I would bleed them again to rule that out first.

DavidsVolvo · Post by **DavidsVolvo** » 09 Sep 2014, 13:59

Oh, sorry. I did bleed the lines. I hear you and that is the first thing to try. This pedal does not feel like air, which would be a spongy feel as you get some braking. this feels like the pedal goes down 2 inches with no braking and then it gets a hard pedal feel where the brakes work. If you ever drove a car without power assist brakes...this is what it feels like, except with out the 2 inch travel. Any other ideas about the components in the power assist area?

Post by **mecheng** » 09 Sep 2014, 14:20

Probably the master cylinder, you are engaging the secondary piston. I would have this checked out

Post by **jblackburn** » 10 Sep 2014, 09:31

When you bled the brakes, did you sink the pedal all the way to the floor?

I always put a board underneath to keep the pedal from sinking to the floorboard - this will destroy the seals on the MC.

DavidsVolvo · Post by **DavidsVolvo** » 11 Sep 2014, 08:43

Um, well, ya...I did sink the pedal to the floor during bleeding. However, I bled the brakes 5000 miles ago and they worked fine for that time 3 months. This sponginess came on suddenly and immediately.

I noticed there is absolutely no loss of brake fluid. When the MC goes, is it an internal leak...a by-pass? Also, if the MC is the issue, why do I still ave very good braking if you exclude the fact I need to push harder and further to the floor with the pedal? Thanks for hanging in with me on this troubleshooting.

Post by **850 LPT** » 11 Sep 2014, 12:31

jblackburn wrote:When you bled the brakes, did you sink the pedal all the way to the floor?

I always put a board underneath to keep the pedal from sinking to the floorboard - this will destroy the seals on the MC.

I believe you ruined your MC by doing this. Long time ago this happened to me on my Capri with pretty much the same symptoms, although I felt them right after I bled the brakes.
Maybe one of the seals was on the verge of rupture and finally gave in. Did you have to hit the brakes real hard before it happened? It's basically an internal leak when this happens.

For this reason, then I NEVER use the pedal method anymore. If you replace the MC now, do yourself a favor and by a Motive Power Bleeder, you'll be glad you did. I've used mine so many times already on all our cars, it was well worth the money.

Dirk

DavidsVolvo · Post by **DavidsVolvo** » 11 Sep 2014, 12:39

Thanks Dirk...its back into the garage to check this out.

Post by **jblackburn** » 11 Sep 2014, 12:46

A bunch of crud (or burrs on the end of the cylinder shaft) can build up over time with used brake fluid. As the pedal is never pushed down that far, when you travel over it, it destroys the seals.

+1 on the Motive...awesome little thing.