Volvo C70 Soft Brake Pedal.

[Ritchie]

Before all of this debacle I came across a 2004 Mk1 Volvo C70 on ebay which I fancied for a bit of summer cruising wth the kids.

I'd been half looking for a cheap convertible for the summer and as this was extremely cheap with a decent test on it I snapped it up.

It's a really clean car with one owner and only 80k on it with the lovely 5 cylinder warble, anyway it does have a few issues.

When I picked it up the brake pedal was very soft, only really doing anything in what feels like the last inch, but I figured it would be easy enough to sort out

It has had new discs and pads all round recently.

Here it is...

Anyway after I got it home, I gave the brakes on all four corners a bleed, which possibly helped a little but there is still something amiss.

Obviously the master cylinder was the next option so a good used one was fitted and bled again, both from the cylinder and the calipers but still no success.

After a bit of googling it appears that its a common issue, however I can't find anyone that has come up with a solution to it.

I did plug in my code reader to see if I could open any valves in the ABS pump whilst bleeding but I was unable to.

My next move is to either use a pressure or vacuum bleeder and see if I can find a code reader which might activate the ABS pump to bleed it properly.

Looking through the wheels it appears that the pads have been fitted correctly as I had read that if some nugget puts the springs back on top of the lugs on the caliper carrier instead of underneath this can push the piston back by pushing the front of the caliper up.

I was just wondering if anyone on here had come across this issue on a V or C70?

I'm away from the car at the moment and I don't know when I'll get back home, so unfortunatly I'm not in a position to check anything else.

Cheers!

[ChasR]

Good to hear you have bled the brakes. I personally never bleed the brakes using the 'pumping the pedal method' as I've once destroyed the seals due to doing this; so I only ever use an air bleeder on a reservoir where possible. It seems this may not be the case.

With that ruled out:
-To bleed the ABS without the right equipment, the 'cheat's and less effective way is to brake with the car on loose gravel which will activate the pump. This will help get some air out of the pump which can then be done with the next bleeding session. I'd still pump the pedal first prior to going to bleed.
-Check the pads and discs. Sometimes the pads can get stuck in the carriers, due to either being a poor brand of pad (i.e the ears/backing plate is too thick so it jams in the pad) or down to grease congealing ; I've seen this happen with copper grease in some instances before ; I normally use ceramic grease now which seems less susceptible to it. The pads not being free to move in turn can overheat sections of the disc, and effectively unevenly wear the disc. This will result in curse word brakes and a spongy pedal. Here is an example of this happening on my Clio:
-Sticking slider pins. Depending on the design, these can either seize due to the pins having too much dirt in them, the rubber swelling up, the pins depending on the design require lubrication, or the metal around the rubber bushes has corroded, making the rubber effectively 'squash' the slider pins and seize them.

Here are some images demonstrating what I mean regarding the second point.

The squshed rubber slider boots was the issue on my sister's Saab. Changing them made a world of difference to the pedal feel.

[asdajnr]

Are you 100% happy with position of the caliper tension spring?  ...i.e. is the u-bend of the spring correctly positioned between the caliper and the disc like this?


..or is it wrongly placed between the caliper and carrier?

If clip is in correct location what about trying a brake clamp on each brake hose in case there is a weakend one?

To cycle the ABS pump you'll need access to a VIDA-Dice set up. If you join here there's a map of owners with it. I've got it. I'm in North Derbyshire but obviously can't help at the moment.

I've also had in the past a set of cheap pads of which the surface wasn't flat and only outer edges touched the disc. Rectified with decent set.

If it was me I'd:

1. Go through the brake hardware as per ChasR's thought pattern including double checking clip position and how well the pads are contacting the disc.
2. Clamp brake hoses and check pedal feel.
3. Bleed brakes using VIDA or gravel method.

Cheers

Dave

[Ritchie]

Cheers gents,

I'll check out a few of these things when I get back to it.

Much appreciated.