easy way to grease pistons (MOT pass trick)

Moderator: Moderators

Post Reply
ross46
Restricted
Restricted
Posts: 825
Joined: Fri Aug 26, 2011 9:31 pm
My Bike: zxr 400 l6

easy way to grease pistons (MOT pass trick)

Post by ross46 »

right, took my bike to be MOT'd that has all gone terrible (see electrical problems post) either way... passed on everything apart from a couple of stupid things but the mechanic said to me that the brakes where catching slightly more than they should. i didnt want to have to get all new seals etc or even strip the calipers so i greased without removing, this may have been done before but thought it might be helpful for new riders. (will put in pictures later)

disclaimer- i am not a mechanic, this is just a method i devised while doing home maintenance, if you are not confident take to a reputable mechanic to do for you

things you need;
-brake cleaner
-scotchbrite pad
-brass wire brush
-assorted high grade wet and dry (800,1200,1500 i used)
-red rubber grease (you can get massive tubs of it that will last a lifetime for most, or little sachets of ebay for a couple of quid)
-copper grease
-ratchet
-sockets
-phillips and flat screwdriver (i used a long flat blade for leverage)
-allen keys (i replaced all my bolts for stainless socket cap ones-http://www.ebay.co.uk/itm/Tokico-stainl ... 256a0ef0ee)


first step is to remove the caliper from the fork leg. undo the 2 bolts

2. remove the brake pads;
- undo the two bolts that hold the metal plate over the brake pad pin
- remove the circlip on the brake pad pin
- remove brake pad pin. (for tips on how to remove see viewtopic.php?f=121&t=14088)

3. give the pistons a quick clean
- try to remove the crap that sits there because the dust seal has caused it to collect
- i used a brass wire brush, a scotchbrite pad and some brake cleaner for this bit

4. check there is no rust as this can rip the seals.
- if you find this use some high grade wet and dry to try and smooth it off (i used 800 and 1200) until if you run your fingernail over it is smooth

5. push the pistons back into the caliper (remove the resevoir cap to allow for expansion with rags around to catch excess fluid)
- to do this first try pressing them in with your fingers
- if this doesnt work try using a flat screwdriver as leverage
- on mine this didnt work so try using a G-clamp or mole grips. i used mole grips by getting some kitchen roll, folding it up and putting it between the grips and outside of the caliper (mine are painted gold, didnt want to damage... still did on one when i got lazy)
-put the mole grips so that they sit on a flat bit on the outside of the caliper and the face of the piston not the side. and squeeze, you may have to repeat, tightening as you go each time

6. after doing this on 3 of the pistons i put a socket inbetween 2 opposites (you can use other things, someone used a dunlop brick before! but the socket was too hand 18mm i used) to stop them coming out and left the grips on another and squezed the lever until the 4th started to come out
- make sure you dont push it out too far otherwise it'll fall out and youll have to rebleed and probably replace seals

7. once the 4th piston is out i made sure to clean it fully
- using a scotchbrite pad first, try to remove all the crud
- some of my stuff was very stubborn so i used the wet and dry to remove. (dont try scraping with a screwdriver as you will damage the piston)
- once it was clean i used 1500 grade sandpaper to polish the pistons up so they were smooth
- Then get some red rubber grease and smear over the pistons. not massively thick but not a really thin layer
- this bit is optional but what i did was then get some grease and pack it down at the base of the piston to stop the bit on the piston just sitting there and staying

8. push the piston back in
- you should be able to do this with your fingers now, if not use one of the other methods.

9. repeat for the other 4 pistons on that caliper.
- the order i did it in was after pushing the first back in, moving the grips to the opposite piston leaving the socket holding the others. and pumping that piston out
- after the second, move the socket or other part used inbetween the first two and put grips on one of the other ones.

10. repeat for other caliper
- before moving onto the next caliper, put the first one back on with pads in etc to stop the first calipers pistons popping out.
- remember to clean the back of the pads and put some copper grease on the back of the pads.

done... This isnt the perfect method. it is better to split the calipers, remove all the pistons, clean, grease and put back in with new seals. but this method is ok to use occasionally. ive used it when changing pads. and then full rebuild every 2 years when changing fluid. took me about 2 hours for both but had to work out how to do, next time i guess about 30-45 minutes and has made my brakes alot better. wheel turns more freely as the pistons are retracting better.

any questions or suggestions, just ask

Ross
User avatar
KwakKwak
zxr400 oc member
zxr400 oc member
Posts: 462
Joined: Sun Jun 16, 2013 11:10 pm
My Bike: ZXR 400L9 2001
Location: Carrickfergus, Northern Ireland.

Re: easy way to grease pistons (MOT pass trick)

Post by KwakKwak »

I am sorry to have to tell everyone, Ross will not be on the forum for a while due to a typing injury, get well soon mate :smt002
Does the low seat height reflect the low intelligence? Easier to get an asshole onto.
ross46
Restricted
Restricted
Posts: 825
Joined: Fri Aug 26, 2011 9:31 pm
My Bike: zxr 400 l6

Re: easy way to grease pistons (MOT pass trick)

Post by ross46 »

What have I done? :smt017
User avatar
KwakKwak
zxr400 oc member
zxr400 oc member
Posts: 462
Joined: Sun Jun 16, 2013 11:10 pm
My Bike: ZXR 400L9 2001
Location: Carrickfergus, Northern Ireland.

Re: easy way to grease pistons (MOT pass trick)

Post by KwakKwak »

ross46 wrote:What have I done? :smt017
Two nails and a sprained index finger.
Does the low seat height reflect the low intelligence? Easier to get an asshole onto.
ross46
Restricted
Restricted
Posts: 825
Joined: Fri Aug 26, 2011 9:31 pm
My Bike: zxr 400 l6

Re: easy way to grease pistons (MOT pass trick)

Post by ross46 »

Oh yeah that!
Post Reply