Spada proportioning valve rebuild?

Has anyone had a go at rebuilding the linked brake proportioning vale on a Spada? I know Brembo dont make any refurb kits for them. But if someone has had a go and has the some information about the various sealsId be very grateful
Ta muchly thanks

A pm or phonecall to Hook Nose Hicks could be your best bet.

Hi Gwen, have rebuilt a couple of these in the dim and distant past. Think the main problem was seizing of the piston due to moisture in the brake fluid, once it was freed off with a bit of brute force and ignorance the piston was removed and cleaned, the seals seemed OK and the unit worked Ok on re-assembly. Bear in mind any seals for this use would need to be viton, you may be able to find replacements by measuring and matching on t’internet.
Cheers, Gerry.

Cheers Ian and Duffo. I have somehow collected 2 spare ones of these lil buggers I thought Id have a go at renovating them. One came to bits OK, the spring is manky, and there is some build of crud on the piston but that looks like it will clean off,the seals look in good nick. The other one is being a bit more stubborn in getting the circlip (there was some sort of green glue on it) out I have put some plus-gas on it an left it over night.

Hopefully Ill get a working one so that I can swap out the one on the Spada which is being problematic. I think it is partial seizing as the little piston that sticks up isnt moving as far as it used to and the rear brake isnt as effective as it was. The front brake is fine. Have had the rear caliper to bits and it seems fine.

When I tried this long time ago I got it apart and found the rubber grommet type thingy at the bottom was all squashed and distorted, as you say no refurb kit to replace it so had buy a complete new unit. The rubber grommet thingy is what restricts the fluid to the rear caliper, a rod goes through the centre and is pulled up by the piston, and has like a round button on the end that blocks the hole in the middle of the grommet (hydraulic pressure also pushes the grommet down onto it, ensuring a seal ~ it is quite clever how it works), but not if grommet is knacked … then it just works as a brake pipe inter-connect manifold. (No proportioning.) However there may be other designs apparently, which might work differently but that was what happened with that one.

Oh well back from holidays and the saga continues

So I rebuilt one of my 2 spare proportioning valves and went to saw out with the original. MMMMM seems that the spare one I have are of a more modern type and totally different. Bugger!

So while having a think about what to do next I had a quick look at the rear caliper. It looked ok till I noticed that one piston was a little furhter out that the other. So push pistons in and pump em out yup definitely one piston doest come out full width. Ive got a seal kit had so decide to rebuild caliper. Except I can only get one of the bolts that hold the caliper together. The one that is in the sunk hole decide to round. GRRR. I have had an old P09 caliper that I had taken to bits with intention of either flogging it or keeping it as a spare, only one of the pesky nipples is broken. So I had the pistons and pins for that. Anyway I rebuilt that. Freed of my proportionning valve (require the use of G clamps and short piece of tubing. When it did free it went with a bang)

Anyway brake system all back together new pads in calipers and new brake fluid (camplete pain in butt) Take the bike to the nice MOT man to see if the rear brake works. And the the result is back to stage 1. Rear brake is still a very marginal pass. OH poooh.

So I am thinking air in system or the proportioning valve is not right.

One thing I did note is that the old pads seem to actually go over the edge of the disk and wear wierd. It is like they are too large. I dont remember the previous pads being like this.The old pads were bought from MotoMecca so no reason to think they are wrong. Meant to take a piccy but forgot.