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Hi John,
I'm back in Athens at the moment for almost a months holiday, arrived on Thursday evening. The first job Friday was to get the Apache back together and ready for the trip to Naxos where I'll be staying most of the time.
I put a servicable chain slipper on (which I had to borrow from my UK based Apache), a recovered seat, a replacement rear brake caliper and the front brake master cylinder which partially siezed last year. Now it has been on the work bench in my garage at Weston since I arrived back last August, in that time I've regularly checked that everything was OK. I made sure that the plunger still moved freely in the bore and it's been fine.

Despite the numerous beer breaks and other interuptions I had the bike back together and the brakes bled by Friday evening, on Saturday morning I rode the bike to the nearest garage, filled up with fuel and topped up the tire pressures. All fine until Saturday afternoon when the front brake master cyliner plunger again started to 'stick' in the bore.

Right, after removal from the bike and taking the plunger out of the cylinder the heat must be causing the aft seal to become so tight in the bore that it leads to sticking/partial siezing. Why this should have suddenly started to happen after being fine for over ten years I can't explain, maybe a rogue seal or maybe the rubber has had too much of the heat?

Plan A - I masked the surfaces of the plunger with aluminium tape and rubbed the seal with scotch brite to reduce the outside diameter! It won't be so tight in the bore then!! I know it's crazy but I've got to try something, can't do another stint with only the back brake.
Plan B is to find a new seal when I get back to the UK.

After much rubbing put it all back together and bled it last evening. I've intentionally left the bike in the sun from 10.00 this morning, it's 14.50 now and so far so good, the plunger still moves freely!

Leaving for the island on Tuesady so got to get it sorted by then,
Leigh

Hi Leigh,
Good to hear you found time to have a few beer breaks, got to to full precautions against dehydration
If you were in the UK with their wonderful summer you would not have problems with heat expansion, corrosion yes
When looking for seals for the RC i raided a parts book for brake seal kits for Jap bikes in MandP in Swansea, found the diameter I was looking for and modified the new piston to match the length of the original Grimeca piston and accept its spring, so far the mod worked.
Good to hear from you again.
John

Hi John,
That's good info on the seals, thanks! We are going to have to do something to keep our Gilera brakes in good condition because Bob says he can't get anymore of the Grimeca caliper/master cylinder overhaul kits that he used to supply!!

Right now, as well as the plunger seal for the front brake I also need a dust seal for the rear caliper (same as RC 600), and front and rear caliper dust seals for a Nordwest/Crono. I'll hopefully find a seal from our consumable stock at work to fit the plunger but finding capliper dust seals that fit may be harder.

On the Apache sticking plunger seal, it didn't work, it began to stick again but not as bad as before, the brake was still useable. I pulled it apart again and removed more material with a file!!! Put it back together and have been out on it, so far it's not leaking and not sticking!

Leigh

Hi

a few years ago i bought a sealing kit for the Nordie calipers here in Germany.
Piston diameter is 25 and 28mm. There are some nearly the same looking calipers used on Aprilias, but be carefull, they have different diameters.
The source for the seals is

www.he-motorradtechnik.de

Have a look at their Super Moto breaking kits. The HE70 calipers are the right ones.
Just send them a E-Mail at
This email address is being protected from spambots. You need JavaScript enabled to view it. and ask for the sealings. I payed about 8 euro for each kit, but that was some years ago.
The calipers should also be the same as on SP01 02, Crono, CX and GFRs
If you need help, just drop me a line.

ciao Joachim

Hi Joachim,

Thanks for the great info and the offer of help, I'll let you know if I need more assistance.
You're right the same calipers were used on the 125 models you mention.
I'll send an e-mail to the site when I get back home and know exactly what I need. Can you remember if the seal kit you bought included the internal seals and the external dust/water seals?

Also no problems with the Apache front brake today, I'm praying that my 'Bodge job' on the plunger seal lasts for the next three weeks. Off to Naxoz in the morning!!

Leigh

all inclusive
The hp calipers are Grimeca calipers. They just replace the name by their own.
So i suppose also the sealings are original Grimeca.
I still have a set, but i also have a spare set of calipers. So i would not like to give it away

ciao Joachim