Go to Main Site Diff'rent Strokers
For fans of oddball two-strokes everywhere
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Classic Bike Trackdays

Project RSS50
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next
 
Post new topic   Reply to topic    Diff'rent Strokers Forum Index -> Four-strokes
View previous topic :: View next topic  
Author Message
Howie



Joined: 18 Oct 2009
Posts: 466
Location: Kwaksville

PostPosted: Fri Oct 23, 2015 10:13 pm    Post subject: Reply with quote

Quote:
Btw - some say they find it easier with air compressor .. I've tried both and for me the grease gun works best


Got to agree partially on the grease gun approach but...............

Hydraulic fluid & G clamps (oooer missus etc) do it do me every time with loads of mess too.

Best way is to (try to) remove the brake system intact. If you can remove the (or have a spare) handlebar, then clamp the bar in a vice, reservoir upmost of course.

Then, if a single piston caliper, keep pumping (sorry the brake lever Giggity Giggity ) till the piston pushes out in a nice orderly British way.

However & this is where the G clamps come in, if you have dual pistons or more, then you need to stop the advance of the free ones in order to replace the stuck ones.

So, just pop the clamps on the ones that move freely, till the stuck ones move. You will need to adjust & mess about with clamps but its a lot cheaper than buying a set of brake piston removal tools which will only work on certain pistons.

What you are aiming for is for all the pistons to be at least 3/4's out. Then they can easily be removed with a set of plumbers pump pliers.

I hope that makes sense Very Happy
Back to top
View user's profile Send private message
Top-shaggy
Show Star !
Show Star !


Joined: 05 Mar 2011
Posts: 1675
Location: Derbyshire

PostPosted: Fri Oct 23, 2015 10:55 pm    Post subject: Reply with quote

Okay...

If the caliper is still connected to the master cylinder then Mr H idea is clearly the best to start with..

The greasy gun approach is my fix for callipers not connected to a brake line.. (Erm.. like the scrap yard challenge ones sold on eBay with the description.."low mileage in excellent condition"..NOT!)

its Impressive how easy grease gun works
Grease gun plus G clamps for more than one piston..

I'm sure their are many different ways to do it.. This is but mine with the tools available in the shed Smile
_________________
We are where we are...
Back to top
View user's profile Send private message
The Cameraman



Joined: 22 Aug 2015
Posts: 608
Location: Lancashire

PostPosted: Sat Oct 24, 2015 1:58 am    Post subject: Reply with quote

Top-shaggy wrote:
The Cameraman wrote:
Hi Shaun,

so what's the 'grease gun tip' matey?



Its the way I get rusted and seized pistons out the callipers ..
Simply put... Put a surrogate bolt into the brake pipe hole to block it off, slacken the bleed nipple and put a grease gun onto the nipple... And pump.

Its amazing how easy it pushes out the piston so you can replace piston and seals etc

The only down side is having to clean out the grease in the calliper - but that's a very small price to pay and takes a couple of minutes

Btw - some say they find it easier with air compressor .. I've tried both and for me the grease gun works best Smile


Hi Shaun,

nice one. I'll try that the next time I'm doing a calliper stripdown.
_________________
Kindest regards


Reggie
Back to top
View user's profile Send private message
The Cameraman



Joined: 22 Aug 2015
Posts: 608
Location: Lancashire

PostPosted: Sat Oct 24, 2015 2:01 am    Post subject: Reply with quote

Howie wrote:
Quote:
Btw - some say they find it easier with air compressor .. I've tried both and for me the grease gun works best


Got to agree partially on the grease gun approach but...............

Hydraulic fluid & G clamps (oooer missus etc) do it do me every time with loads of mess too.

Best way is to (try to) remove the brake system intact. If you can remove the (or have a spare) handlebar, then clamp the bar in a vice, reservoir upmost of course.

Then, if a single piston caliper, keep pumping (sorry the brake lever Giggity Giggity ) till the piston pushes out in a nice orderly British way.

However & this is where the G clamps come in, if you have dual pistons or more, then you need to stop the advance of the free ones in order to replace the stuck ones.

So, just pop the clamps on the ones that move freely, till the stuck ones move. You will need to adjust & mess about with clamps but its a lot cheaper than buying a set of brake piston removal tools which will only work on certain pistons.

What you are aiming for is for all the pistons to be at least 3/4's out. Then they can easily be removed with a set of plumbers pump pliers.

I hope that makes sense Very Happy


Hi Howie,

yeah I've taken this route myself in the past on other machines and it wors fine.

Sometimes I've even swapped the dodgy calliper onto one of my other bikes, to pump it through. OK you have to re-bleed it but it's always good to have a bit of new brake fluid!
_________________
Kindest regards


Reggie
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Tue Oct 27, 2015 5:18 pm    Post subject: Reply with quote

Thanks for the advice chaps.

The brake systems have been removed in tact so I can use the master cylinders to (try to) get the pistons out, then it looks like I've a few messy hours with a wire brush ahead of me.

The front brake was adequate for the performance of the bike, but obviously not what it should be. The brake pad retaining screw is seized in the calliper. It’s had a squirt of WD40, I’ll have to put the calliper back on the fork leg so I can get some leverage on it to release it. A new calliper is £116 on eBay so not bad for what it is. You don’t get many hours labour for that these days, but it’s not my way. If I find it needs pistons and seals then maybe a new one is the way to go, the new one comes with brake pads too. I’ll get a price for genuine parts as well, they’ve been surprisingly reasonable.

The rear brake hardly worked at all, and the rear disk is so worn the it has cracked. I think only one of the pistons has been moving so it’s been trying to bend the carrier to make the brake work. Same deal as the front really, with a new one costing £80 on eBay.

Surprised you’re using High Temperature paint on your callipers, surely they shouldn’t get that hot? I can see they’ll get radiated heat from the hot disk, but the calliper shouldn’t be in contact with anything really hot.
_________________
Light is right.
Back to top
View user's profile Send private message
Howie



Joined: 18 Oct 2009
Posts: 466
Location: Kwaksville

PostPosted: Wed Oct 28, 2015 12:18 pm    Post subject: Reply with quote

Quote:
but the calliper shouldn’t be in contact with anything really hot


No but hydraulic fluid does get hot. Not sure what temp it can get to in normal use?

But the main reason I use VHT or caliper specific paint is that it is more resilient to the effects of hydraulic fluid when bleeding the brakes & the spillage you can get. Unless you use DOT 5 (5.1) which doesn't have the same paint stripping qualities of DOT 4 but I have heard it's not as good as DOT 4???

Hope this helps Arlurt
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Wed Oct 28, 2015 2:51 pm    Post subject: Reply with quote

That all makes perfect sense.

First job is to get the callipers stripped and see if I need new pistons and seals. If I do, I'm be very tempted to just buy new callipers.

I hope new parts are not required, I do quite like dabbling and doing things my own way. Very Happy





Pistons appear in good order, they look like stainless. Seals are OK but a bit of corrosion in the seal groove which made them tight on the pistons. The alloy body castings have suffered in the British weather but I think they're recoverable. Another plus is that I think I'm the first person to take them apart so no bodges.
_________________
Light is right.
Back to top
View user's profile Send private message
The Cameraman



Joined: 22 Aug 2015
Posts: 608
Location: Lancashire

PostPosted: Wed Oct 28, 2015 11:10 pm    Post subject: Reply with quote

Hi Arlurt,

looking well worth speeding a bit of TLC on those callipers.
_________________
Kindest regards


Reggie
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Mon Nov 02, 2015 7:34 pm    Post subject: Reply with quote

Twenty minutes with a brass wire brush and the best kitchen Jif (or is it Cif) and the calliper half doesn't look much better.





There's a place up the road that does vapour blasting, I think I'll pay them a call and see what they can do.
_________________
Light is right.
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Fri Nov 06, 2015 6:12 pm    Post subject: Reply with quote

I don't know if I've done the right thing or not... Confused

A genuine new front brake calliper is £116, and a new rear calliper is £82. Both come with new pads.

I've just dropped my front and rear callipers, foot rest hangers, foot rests and a bracket off to be vapour blasted at a cost of £70. The front pistons and seals are OK to re-use but the rear pistons and seals are shot, so there's another £25. I'll have to repaint the blasted callipers, and probably swap the corroded zinc calliper bolts for stainless.

I'm hoping that my rebuilt brakes will be as good as new, and that my painted finish might weather better than the anodised standard finish which has suffered so badly in the hands of the last seven 16 year old owners in just 17,000 miles.

I get the blasted parts back tomorrow, hope I feel happier about it when I see them.
_________________
Light is right.
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Sat Nov 07, 2015 2:06 pm    Post subject: Reply with quote

I picked up my vapour blasted parts this morning, he's done a really good job:



Just compare the pictures of the front calliper with those above.





Now, do I paint them or leave them as bare alloy?
_________________
Light is right.
Back to top
View user's profile Send private message
gagster55
Show Star !
Show Star !


Joined: 04 Dec 2006
Posts: 217
Location: West Yorkshire

PostPosted: Sat Nov 07, 2015 2:46 pm    Post subject: Reply with quote

anodise................ Wink
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Sat Nov 07, 2015 2:57 pm    Post subject: Reply with quote

How?

Or how much?
_________________
Light is right.
Back to top
View user's profile Send private message
arlurt
Show Star !
Show Star !


Joined: 28 Nov 2006
Posts: 680
Location: North Yorkshire

PostPosted: Sat Nov 07, 2015 5:48 pm    Post subject: Reply with quote

Too late...

I masked the mating faces, threads, hydraulic passages and piston bores, then acid etch primer, alloy wheel silver and two coats of clear lacquer.



Baked for 90 minutes at 70 degrees when she wasn't looking.

I thinks they've come out well. Very Happy

I picked up stainless fasteners at the auto-jumble this morning, and a two nice alloy torque arms, one for the rear brake of the special and one for the KH250. New rear pistons and seals are on order, as are new stainless bleed nipples.
_________________
Light is right.
Back to top
View user's profile Send private message
Top-shaggy
Show Star !
Show Star !


Joined: 05 Mar 2011
Posts: 1675
Location: Derbyshire

PostPosted: Sat Nov 07, 2015 5:54 pm    Post subject: Reply with quote

I do as well. Look like new Smile
_________________
We are where we are...
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Diff'rent Strokers Forum Index -> Four-strokes All times are GMT
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next
Page 5 of 7

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group.  Installed, administered and modified by  Diff'rent Strokers © 2006-2018.