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Brake fluid damage to plastic
Posted: Tue Jun 04, 2013 5:31 pm
by fatboy
It seems the seal under the cap on the clutch master has given up. On the way to work I noticed some 'snail trail ' marks over the speedo.
When I got home I noticed droplets of fluid over the speedo, inside the lower screen ect.
Most I washed off with no problem but the speedo screen has opague smears and a few white spots on it now.
Any ideas what may shift it ? ?
Re: Brake fluid damage to plastic
Posted: Tue Jun 04, 2013 7:24 pm
by blinkey501
fatboy wrote:It seems the seal under the cap on the clutch master has given up. On the way to work I noticed some 'snail trail ' marks over the speedo.
When I got home I noticed droplets of fluid over the speedo, inside the lower screen ect.
Most I washed off with no problem but the speedo screen has opague smears and a few white spots on it now.
Any ideas what may shift it ? ?
Mmm. You will be really lucky to remove it. Try T cut, but I fear that is optomistic

Posted: Tue Jun 04, 2013 7:51 pm
by D-Rider
Plastic polish.
If that doesn't get down far enough to begin with, go for the finest grade of wet and dry and then finish off with plastic polish.
I've used Xerapol and found it very good:
http://www.youtube.com/watch?v=ibzgMAxOYaA
My son also sent me these links for other products he has heard to be good:
http://www.youtube.com/watch?v=9qvGnFecVDs
http://www.youtube.com/watch?v=mKHeZusdTTM
Re: Brake fluid damage to plastic
Posted: Tue Jun 04, 2013 9:22 pm
by mangocrazy
fatboy wrote:It seems the seal under the cap on the clutch master has given up.
To be honest, I think you'll find that the anodising on top of the crap cast aluminium that the master cylinder cover is made of has started to lift and let fluid past. I've seen this happen on two Falco master cylinder covers, one of which is my pampered 2008 Falco.
It's basically a shit piece of work (the cover, not the seal) and your best bet is to replace it with an aftermarket item or get the cover vapour blasted and re-coated with something impervious to brake fluid. The seal will be fine and can be transferred to your new or refurbished cover. Aftermarket covers will be machined out of superior quality ali and then anodised - they should last for ages.
Ironically the black plastic cover on my 1991 Ducati m/cyl is still perfect. I really don't understand why manufacturers put really unsuitable materials next to brake fluid.
Posted: Tue Jun 04, 2013 9:38 pm
by D-Rider
Repainted my master cylinder cap and finished it with a resistant lacquer - it's been fine since.
Posted: Wed Jun 05, 2013 6:12 pm
by fatboy
Thanks all, the cap is plastic, the fluid seems to be leaking from res to master entry point, dribbling onto my new shorty levers ( aaaargh )
The master seems to be giving up bigtime, I understand they are not repairable
More expense at the wrong time !
Posted: Wed Jun 05, 2013 9:13 pm
by D-Rider
fatboy wrote:Thanks all, the cap is plastic, the fluid seems to be leaking from res to master entry point, dribbling onto my new shorty levers ( aaaargh )
Ah yes you're quite right - sorry, Mango sucked me in to recalling what I did to fix my brake reservoir lid.
Posted: Wed Jun 05, 2013 10:23 pm
by mangocrazy
Sorry - confused brake with clutch... Brake m/cyl cover is definitely aluminium. I'll take your word that clutch m/cyl cover is plastic.
Apologies...
Posted: Thu Jun 06, 2013 5:43 pm
by fatboy
Closer inspection reveals the leak is from the res end of the short piece of flexi that connects to the master.
Undid the mounting bracket, released the clip, pushed the pipe further onto the res outlet.. appears to be fluid tight,
Thats what i thought yesterday as well !
Can only assume flexi pipe has lost that pliability that makes it seal.
Brake ? Clutcch ? Master ? Slave ?
They are all mischevious bastards just waiting for the moment to torment you

Posted: Thu Jun 06, 2013 6:55 pm
by mangocrazy
It does still have the spring clip to seal it at the reservoir end, doesn't it? And is the rubber OE? I've used the wrong type of rubber in the past for brake fluid and it can 'sweat' alarmingly.
Posted: Sun Jun 09, 2013 7:34 pm
by fatboy
Its all original kit, just reached the end of its working life.
Ishortened the flexi, doing away with the swelled end that wouldnt seal, but fluid is coming out from under the res cap.
I washed off spillages I could see, what I didnt see has done some harm to the paint on the fairing upper where it curves in to meet the fairing lower, below the SL decal,also clock faces and screen inner
Where does one find Xerapol ?
Posted: Sun Jun 09, 2013 8:13 pm
by D-Rider
fatboy wrote:
Where does one find Xerapol ?
I think I got mine from Halfords but their website does not mention it now.
Plenty of choice on ebay
http://www.ebay.co.uk/sch/i.html?_trksi ... &_from=R40
Posted: Mon Jun 10, 2013 6:18 pm
by fatboy
Thanks D-Rider, just ordered some, needless to say I wont be using it until new seal and pipe arrive.
Griff tells me the seal is not an available spare, you have to buy the complete res unit, so he's sendind me a good seconhand one, no charge

, he is a top lad !
So thats a fiver in the post for tea and biccies