First, I know Pizzaguy will chastise me as I store my XF in the winter and only start it once a month and drive occasionally on a nice winter day. I had my state inspection done last fall at the dealership where I purchased my XF (as there is no charge) and had them replace/flush the brake fluid. Brakes were mushy before this, had to pump a second time to get the pedal up. I did not drive much the rest of the year but before storing for the winter the brake pedal again needed to be pumped a second time to feel comfortable stopping. I went for a spin last week and now have to pump the pedal several times to brake. I tested the master cylinder with the car off and had a stiff pedal on the second push. I took my foot off the brake and pushed again, and the pedal was solid almost immediately. Any ideas what may be causing this "no" brakes issue. BTW, this is not my daily driver and only has 29k miles. Thanks in advance.





 

If you start it once a month I will make no negative remarks.
I'll let the more knowledgeable "mechanic" types here answer you question. I don't even bleed my brakes, I go to tech days and get others to maintain my car while I work on electrical/electronic and sound system issues.

 

I had this exact problem 2 years ago. I had a mechanic friend of mine tell me that air must have leaked in while sitting and I should bleed each brake a little to find the culprit.... so I did. It sort of "fixed it ....NOT". I decided to empty the master cylinder bowls and add new fluid (Pentosin super DOT4). I bled the entire system starting with the rear farthest from the master cylinder. I thought about buying self bleeders but with the help of my fiance all went well. All new fluid and problem solved.

 

Thanks, but I'm not sure how air can get into a closed system and the brake fluid was replaced/flushed with pressure to pass through the ABS. So, this brake fluid is less than 6 months old and brakes were fine after this procedure was done for a few months.

 

I know you MUST use Pentosin super DOT4 brake fluid with our cars. Mine is an 05 and I would bet it was the original fluid (58,000 miles).

 

Maybe this will be of some help. Have you ever replaced the brake hoses? They break down as they get older and get weaker.
They can expand under pressure which may cause your pedal to get mushy. Also use a flashlight and look for any weeping of brake fluid around the connections of the hoses and the calipers.

 

Thanks, I have not replaced the brake lines... I will check for leaks or bulging lines this week and will most likely replace them as they are 18 years old.

 

Wanted to let you know I store my 04 Coupe November through April every year. I do not start it while it is stored. Several years ago I parked it for the winter and had a firm brake pedal . When I was taking it out of storage the brake pedal went to the floor. There were no leaks and the brake reservoir was full. I bled the brakes and everything was fine. Never happened again. Just wanted to let you know what I experienced.

 

I like the recommendation that tells you to look at lines. But I also know that there have been a few owners on our Facebook pages that have had to replace the master cylinder assembly. In any case, this is a MECHANICAL issue, it should not be all that hard to find and fix - not saying it will be inexpensive to fix.

I'd bleed the system again - only thing is, I'd have the work done (as I did) at a "tech day" (or elsewhere) where I know the guys doing the work. I've heard of people who "bleed some fluid out" - but that is not how its done. You must pump until ALL FLUID is replaced. If they bled until the fluid coming out was "clean and new" and stopped, they probably did not get it all, and If they charged you for a few ounces of fluid, they bled the system, they did NOT flush the system.

I bought four cans of fluid, when they were done, I had one unopened can.

 

Thanks for the additional information and possibility that it in fact may be the master cylinder. I will update this thread once I have had a chance to check these possibilities out.

 

Quick update... I did not get a chance to look into this further before I got my right knee replaced this past Monday. As soon as I am able I will check the brake lines and master cylinder and advise accordingly.

 

Get well soon!

 

Ok, sorry for the long delay in getting back to all with the resolution of this problem. The short answer is that it was in fact my master cylinder. It has been replaced and all is great now. I'm all set for a summer of top-down enjoyment!

Thanks, M60A3Driver for the well wishes! I had the other knee replaced in September and all is good with me too.

 

I'm glad to hear that your surgery went well and that you found the issue with your brakes!