Front Caliper Rebuild Kit/how-to

[AlexO]

Chaps,

Simple one. I've got an intermittently sticking front passenger caliper which is slowly getting worse. Since I'll need to borrow an impact driver to get the caliper off for a rebuild anyway I'll change the discs at the same time so just a couple of questions before I buy anything:

1) Rebuild kits: where's the best place to buy? Brookhouse seem mega expensive but I can't find them elsewhere
2) How-to guide: can't seem to find one of these either but I don't want to attempt the job without one, is there one knocking about that I've missed?
3) Vented front discs: are they all the same? I can't imagine they'd be different for ATE/Girling calipers but it doesn't hurt to double check

Cheers

Alex

[Nicholas Lewin]

Morning Alex

I am having endless problems with my 240 - I'll follow up once resolved...

However, some stuff that may help:
Avoid at all costs draining the brake system down completely...
Make sure that you bleed in the correct sequence when you come to refitting everything (you can find the sequence on this forum and elsewhere)
If you are not replacing the master cylinder, be careful when bleeding not to wreck the MC by pushing through your normal brake pedal position and taking a possibly corroded rod thru' the rubber bushes
Personally I am not convinced that power bleeding is helpful. doing it the old fashioned way seems to have better results
The 8-way spider valve (distribution manifold) on the front LH chassis leg is a potential problem. Given the age of your car, this object is merely a machined distribution point for the rigid brake pipes. It has no moving parts or valves in it and nor has it got a pressure switch (earlier ones did). It does have the potential to trap air in it tho'. You need to watch for that and possibly bleed lines at the manifold itself
Classicswede can sell you refurbed calipers as well as hoses and so on as an alternative to Brookhouse. Also try the boys at FRF Swansea (Volvo agent) you are knowledgeable and reasonably priced - tell them that you are on the VOC forum for discount

Good luck, Nick

[AlexO]

Nick,

Thanks for that. Having done work on the front brakes before I'm fully aware of the bleeding in sequence/master cylinder/power bleeder vs. old fashioned method/spider valve problems because I managed to make all of those mistakes in one day a few years back! A good reminder is never unwelcome though.

New vented discs are on order but if anyone's got any more ideas on the rebuild kit I'd be grateful.

Thanks

Alex

[Clifford Pope]

Originally Posted by Nicholas Lewin

Avoid at all costs draining the brake system down completely...

I've always managed to avoid draining any of it when replacing components.
Make up little tapered wooden plugs, the size of golf tees, undo a hose joint and plug the end of the pipe, and the other one. Then remove the caliper.

Fill the replacementcomponent with fluid with a syringe, turning it around so that all the surfaces inside are wetted, and fill to the brim at the pipe enties. Plug these with the plastic plugs that come with new items, or make/find similar.

Replace the component. Quickly whip out the plugs and connect up the pipes, leaving them half a turn loose. Very gently press the brake pedal a small amount, and have someone watch the joints for air bubbles/fluid. Just like slackening a bleed nipple on a domestic radiator.

Then tighten, and with luck the brakes will be hard and not need bleeding.

You can use the same technique to replace a master cylinder on its own.
The secret lies in only doing one component at a time, not stripping everything.

[AlexO]

Thanks Clifford. I can assure you I had no intention of draining down the brake system in any shape or form though, that just sounds dangerous.

Still on the hunt for a caliper rebuild kit by the way, any ideas?!

Alex

[AlexO]

Just a quick update.

Since I've already spent too much on replacement vented discs and I can't find any replacement calipers or caliper rebuild kits in my price range (being a poor young engineer) I'm going to replace the discs and pads anyway. I suspect the sticking is being caused by a build up of grime around one of the caliper pistons because of a torn dust boot so whilst I've got the calipers off to do the discs I'll try and give this a clean. I've bought a caliper seal kit but I'm very reluctant to completely remove the caliper pistons, is there any way I can replace the dust seals in situ? As a side note I replaced the master cylinder two years ago and bled the whole system with new fluid about this time last year so I'm confident the brakes are otherwise in good health.

All advice gratefully received,

Alex

[Bugjam1999]

You can definitely change the dust seals in place - I did that last time I replaced discs and pads as a couple were torn.

I found it easiest to remount the caliper on it’s mounting bolts with the pads and discs removed, and then spin the steering wheel all the way left or right (depending on which you’re working on) to improve access and see what I was doing.

Then clean everything thoroughly with cans of brake cleaner and a toothbrush (put a suitable container on the drive first, an old/cheap washing up bowl works well or a big oil drain container if you have one). Then pull a torn dust cover off and do the same again to get any crud that made it through the cover off the piston. Only then can you push the piston back into the caliper.

The dust covers have a spring clip as part of them (obvious how it works when you see your new ones) that sits over a ridge on the caliper, you’ll need to clean this ridge carefully to allow the new clip to go into place- again obvious when you look at it. I think that took a bit of scraping with something- a small screwdriver or a seal pick.

Then put the seal in place and press round the edge with your fingers to get the clip over the ridge and sit snugly- a tiny smear of grease on the ridge will allow the seal to slide over it easily.

That’s quite a long explanation which might make it sound complicated, but it’s really not- once you’ve done one you’ll swap all the others really quickly. Just get everything as clean as you can.

Cheers

[AlexO]

Bugjam,

Thank you so much! Thats exactly what I wanted to hear, really helpful advice and letting me know exactly what to expect. I'll be doing this on monday/tuesday so expect an update then.

Thanks again,

Alex

[Clifford Pope]

That's really helpful. I struggled once to try to fit a new cover, as the old one seemed to have rusted and there was just a flappy bit of rubber stuck between the piston and the pad. I was trying to fit the new one with the disc in place, so couldn't get proper access and couldn't see what I was trying to do.
I needed the car so just gave up and left it off. It's obvious really from your guide.

[AlexO]

Bugjam, if we ever meet in person I owe you a beer. Your advice was spot on.

Discs, pads and dust boots changed, easy peasy. Sticking caliper seems a little less "sticky" and I'm hoping that, with the new disc and pad combo being thicker, a different part of the piston bore should be in contact with the new boots which should hopefully prevent any problems for the time being. I'll certainly think about a reconditioned caliper when funds allow though.

Now just to fix the exhaust then I can start thinking about go-faster bits. Fun fun fun....

Cheers,

Alex