18 replies to this topic

[TYREDNGRUMPEE]

I've been bashing on about disc bobbins and such, so when I found I was able to buy brake cleaner for less than £2 a can, I went out on a limb, bought two cans and gave the whole system a seeing too and a fresh fluid transfusion.

 

The braking front and rear is much improved, but I've noticed that portions of some of the piston dust seals have "rukked up" and are protruding slightly from the working piston face of the calipers, around the circumference of the pistons. Most likely they've met with WD40 and have expanded over the years.

Some are worse than others, some none at all and the rears worst of all, but they are working 100% perfectly well for now.

 

Only one of the small front pistons on the rhs seems to be displaying a tendency to bind (and then, only slightly).

This means the corresponding disc is running hotter than the other.

As I am running sintered pads atm, some of the heat is being transferred to that caliper and am thinking about buying some organic pads for the time being.

I'm not experiencing any nasty fade, warp or binding in current use and wouldn't have known any better if I hadn't gone postal with the brake cleaner.

But it is obvious that at some stage I will have to dismantle and service the buggers.

In your experience, should I do it now in the bud of Spring/Summer or the depths of Winter.

I can buy a kit like this

http://www.ebay.co.u...EYAAOxyLN9SijoU

or ask Powerhouse to do it for me. £53 + £53 + £39 + carriage.

http://www.powerhous...ild-service.php

 

What are the hurdles to overcome?

Anyone used Powerhouse themselves?

 

I'd be interested to know. Thanks. Pete

Edited by TYREDNGRUMPEE, 16 May 2016 - 10:14 pm.

[dapleb]

http://www.carpe-tdm...l=&fromsearch=1

I ewesed powerhouse for the parts and found them extremely helpful. they also do the caliper half o rings so you can completely split to do a thorough job.

Gettin pistonias out of 20 year old calipots was fun! Other than that, the job is quite straight forward. .... But I would also be happy to give em to powerhouse for rebuild and considering the man/lady boy hours I spent on em their price seems very good!!

As fur time o year. I would def do sooner than winter as the cold will worsen the binding and ya might end up will a flower pot disc.

If ya need lend of piston removal tool just shout.

[Cappo]

Well I think mine cost about £40 to do both front calipers, so £106 plus P&P is a fair hike, although not bad for the job.  It's not difficult, slightly fiddly at times but a couple of hours will see it done (not including your chosen weapon of bleedage but you'll have to do that either way!).

 

Someone recommended a pair of piston pliers which are a godsend, but compressed air will blow the pistons out easily enough (use an air blower with a tapered nozzle, straight into the banjo hole).

[TYREDNGRUMPEE]

Thank ewes all.

 

It is comforting to see photographs of split calipers and know that someone has been there already. 

So then I've gone ahead and I've ordered a kit from Powerhouse for the front set and a pair of piston grips/pot of red grease from the bikers toolbox.

 

http://www.bikerstoo...info_L6212.html

http://www.bikerstoo..._600025243.html

http://i.ebayimg.com...9SijoU/$_57.JPG

 

I've got a few spade fuses tucked away somewhere (handy tip) and spudger tools that I use to mend broken mobile phones.

 

As it turns out, I have a complete spare set of calipers + master cylinder that Rolfie passed on to me.

They're mullered next to the ones on my bike, but were very handy when it came to the brand new pads that they were fitted with.

I may very well service them as well afterwards if I come out the other side of this in one piece.

 

So I have a cunning plan to ease the pistons out as far as I dare, refit the calipers to the stanchions, loosen/tighten the caliper half bolts, bleed nipples and banjo bolts one by one, then go from there. Hopefully this should minimise grunting and cursing.

Edited by TYREDNGRUMPEE, 17 May 2016 - 10:23 am.

[TYREDNGRUMPEE]

Well I think mine cost about £40 to do both front calipers, so £106 plus P&P is a fair hike, although not bad for the job.  It's not difficult, slightly fiddly at times but a couple of hours will see it done (not including your chosen weapon of bleedage but you'll have to do that either way!).

 

Someone recommended a pair of piston pliers which are a godsend, but compressed air will blow the pistons out easily enough (use an air blower with a tapered nozzle, straight into the banjo hole).

 

I've already spent about 80 squids so far.

Thanks for the encouragement.

Fingers crossed it will only take a sunny afternoon.

This is all your fault btw.

[Cappo]

 

 

This is all your fault btw.

 

 I've yet to update that thread, there *is* news but it's not great, just something else I need to check before I post!

[dablik]

TNG i expect this will be a walk in the park for you matey, i used a dental pick to pull the old seals out, no messing around getting them out, and getting them back in well, it's a bit fiddly at first but i'm very proficient at it now  used the blunt side of the dental pick to tease the new ones into place..

[RolfieB]

If you need a hand Pete, you know where I am, but then again you'd need to do it at yours I suppose. Just in case it all goes pear shaped.

Need to get that socket set to you still.

BTW. Bird passed it's MOT no advisories. 

Edited by RolfieB, 17 May 2016 - 05:13 pm.

[TYREDNGRUMPEE]

Just been and bought another two large aerosol cans (large 500ml) of brake cleaner. £1.10 + vat ea = £2.64. Andrew Page factors. (They're on special)

 

TNG i expect this will be a walk in the park for you matey, i used a dental pick to pull the old seals out, no messing around getting them out, and getting them back in well, it's a bit fiddly at first but i'm very proficient at it now  used the blunt side of the dental pick to tease the new ones into place..

 

I'll be using allsorts I think. I'll also have a handful of plastic cotton bud shafts to hand. Easily modded, non scratchy and disposable. 

 

If you need a hand Pete, you know where I am, but then again you'd need to do it at yours I suppose. Just in case it all goes pear shaped.

Need to get that socket set to you still.

BTW. Bird passed it's MOT no advisories. 

 

Rolf! I did mean to ask about the bike. Need to see those LEDs. Mine has passed too. The examiner looked at it and said the front end brake wise was "ah, good enough I suppose". Nice chap.

Your front end forkwise, is working better than ever, which has spurred me on to fettle the brakes. If you do fancy a G2G lettuce know.

I'll free a day up if I have to and I also see that there is another Bank Holiday around the corner. Hope to have the brakes done by then.

[RolfieB]

Just been and bought another two large aerosol cans (large 500ml) of brake cleaner. £1.10 + vat ea = £2.64. Andrew Page factors. (They're on special)

 

 

I'll be using allsorts I think. I'll also have a handful of plastic cotton bud shafts to hand. Easily modded, non scratchy and disposable. 

 

 

Rolf! I did mean to ask about the bike. Need to see those LEDs. Mine has passed too. The examiner looked at it and said the front end brake wise was "ah, good enough I suppose". Nice chap.

Your front end forkwise, is working better than ever, which has spurred me on to fettle the brakes. If you do fancy a G2G lettuce know.

I'll free a day up if I have to and I also see that there is another Bank Holiday around the corner. Hope to have the brakes done by then.

Unfortunately I'm working the Sat & bank holiday Monday. Off this coming weekend, if you fancy a catch up. Or will you be fettling your brakes.

[TYREDNGRUMPEE]

A successful days caliper scraping.

Shame about the weather though.

It seems my problems stemmed from the alloy corroding behind the first outer dust seals and then pushing the seals out of their seats against the pistons.

The smaller pistons were the worst as they are lower and seem to collect all the filth and moisture.

The calipers worked fine. Just the imbalance between the action of all the pistons seemed to mess it all up.

 

The seals were in good nick and I've kept them by.

 

Looks like this may become an annual ritual. (thereby saving the need to buy a seal set every time)

 

Removed pads and used some stout yet thin card to protect the faces of the discs and pumped out the pistons, knowing that the disc would prevent them from popping out.

 

 

Meant that I had to top up the master cylinder reservoir to get a full draw, but I made sure that it was practically empty on the last stroke

 

 

Did the awkward bits of loosening the caliper halves, bleed nipples and banjo bolts while they were still attached to the bike. No stress.

Finally found a use for my 3/8 ratchet, as it fitted the only 6mm hex socket I had. Result.

 

 

The calipers fell apart easily

 

 

Used my new gripper tool to ease the pistons out

 

[dapleb]

Noice wan.

[dmmsta]

Could anyone share links to the piston pliers.

 

I've found a couple on Amazon / eBoo, but want to make sure they're the correct thing - I assume it's a 1 size fits all affair...

 

Does £14-20 seem about right?

[Catteeclan]

Got mine off Ebay some time ago.

 

http://www.ebay.co.u...M4AAOSwEK9XAX7K

 

Haven't had loads of use but they still look and work perfectly.

Edited by Catteeclan, 22 May 2016 - 09:03 am.

[muddy]

I had snatchy brakes, suggesting the need to strip the bloody things again, but the warm weather has disappeared the problem, ta ra, yipee.

[dmmsta]

Got mine off Ebay some time ago.

 

http://www.ebay.co.u...M4AAOSwEK9XAX7K

 

Haven't had loads of use but they still look and work perfectly.

Them's the ones I was peeping at

[johnschmidt]

While people are on about calipers I wonder if anyone can tell me the tightening torque for the font caliper bolts on a 900abs. Took my calipers off the other day for a wash and brush up and not sure whether to tighten as much as possible, or to a specific torque. Ta.

[Studley Ramrod]

40Nm bod.

[johnschmidt]

Thanks for that Ramrod.