2007 V50 Spongy brakes

[sthodgson]

Hi all,

I've never been overly impressed with the brake feel of the V50, but they did work as they should until about two weeks ago.

They have become very spongy, so much so that I can push the brake pedal pretty much to the floor, with moderate force, when the car is idling in neutral. The pedal seems to be far longer than it used to be and I had a slightly scary moment coming off the motorway the other day. The car did stop, but it felt like it wouldn't at one point. If it is pumped it will firm up, but I can still press it almost to the floor. I didn't think this was normal.

I took it into the local specialist I have used many times today. They are very good, and have done great work in the past. The guy took it out for a test, came back and said it didn't feel any different to any other S40/V50 that he has driven and all was well.

Is it just in my mind then? I'm certain the brakes are not performing as they were before. Could it be the hot weather? It doesn't seem like fade, as I used to have that in my old car - the pedal was still firm, but it just didn't stop!

I have searched the forums, and it seems that it could be a vacuum hose that is the problem. Is there anyone out there that has had a similar issue and found the fix?

2.0D, 102K miles. Pads changed all round last October. Brake fluid changed last April and is at correct level and looks healthy.

It's alright someone saying the brakes are ok, but I'm worried as they certainly don't feel it.

Many thanks,
Sam

[IanDW]

My sons V50 D4 has just developed the exact same symptoms you described last year ie spongy brake pedal. He noticed it last week when starting up first thing in the morning, the pedal almost touches the floor but does pump up with some effort. Definitely unsafe to drive though. Just wondering if you managed to find out what the problem was and how you fixed it, or if anyone else can chime in. Thanks very much. Ian.

[sthodgson]

Hi,

It was a strange one that never really had an outcome. I took it to the local specialist, who took it out for a drive, and said he was able to easily provoke the abs to activate on a good dry road, so no problem found. I'm not sure if it was me just looking for a problem, but after being assured the brakes were ok, I accepted them. To be honest, they haven't been a problem, and although I could probably push the pedal to metal when stationary, it's never happened when mobile and it's never felt under-brakes. Maybe the pumping it helped.

Strangely I actually quite like the brakes now, but they are not as firm as our auto xc90, the brakes on which I really like.

I suggest taking it a Volvo dealer or specialist just to see what is wrong, because there could be a leak. Have you checked the levels? Is it Volvo brake fluid?

Cheers,
Sam

[IanDW]

Thanks for your reply Sam! The fluid level is fine, it did need topping up a month ago when the warning light came on, I suspect due to normal pad wear. The fluid used was supplied by Volvo so I assume it's the right stuff! It's definitely not safe to drive, the pedal movement required to slow down is inconsistent. I'm leaning towards a defective master cylinder. We have an independent Volvo specialist nearby who seems to have a good reputation as far as I can make out, I'll contact them. Thanks again for your input.

[paddyred]

I have had this on other vehicles. They where a little more historic i.e. land rovers etc however it turned out to be on around 3 occasions that it was a leak in the brake servo or a leak in the vacuum lines supplying the servo. The brakes should feel slightly "soft" however they should still work well on a normally functioning servo. In a system with poor vacuum or a faulty servo you can pump the brake pedal and it will firm up quickly however brake performance will reduce. Simple way to test the servo for basic functionality although this cannot diagnose small leaks:

Start with engine switched off and pump the brake pedal until it goes hard. This will remove the vacuum "charge" from the servo. Now with you foot pressed on the brake, start the engine. The brakes will begin to feel softer and "spongier" than they did before and your foot will sink into the brake as the vacuum builds up, don't pump the brakes as you start the engine as you wont notice the change as easily. If this happens the servo is functioning correctly.
This is also a great way to test if the brakes are actually spongy in themselves. If with the engine off the pedal doesn't eventually go hard from pumping then something is wrong in the system!

[IanDW]

Thanks Paddy.
On our car, with the engine off, the pedal almost goes down to the floor. If you pump it several times it hardens up a bit (ooh err Mrs!) but will lose pressure and goes soft again. I'm told that is a symptom of a dodgy master cylinder. I will try your servo test as well. Cheers!

[paddyred]

That certainly sounds like an issue with the valves in the master cylinder! If there's no fluid loss but your pedal goes to the floor its time for a new master cylinder I would say!