Brake trouble

**MSTRS:Me** · 18th August 2008, 17:24

Originally Posted by trademe900

took it to honda shop... it's fucked. not only would it need seals but the pistons are fucked themselves.

Got another caliper on the way now

.

To close things off i'll just say that all in all i'm pleased i even looked into this... I'm sure it could have easilly been overlooked and then i possibly could have had a proper seizure while riding. Just thinking about it, i could have braked, brakes wouldnt release/lock rear wheel and someone could have taken me out from behind... game over.

Precisely why I counselled you against trying to do it yourself, early in this thread. Some things are too important to leave to chance etc.

**racefactory** · 18th August 2008, 17:48

Thanks all, I will definately refer back to this thread when it comes to bleeding the system with the new caliper.

**FJRider** · 18th August 2008, 18:00

Better still ask first... help may not be far away.

**Max Preload** · 18th August 2008, 18:39

Originally Posted by trademe900

took it to honda shop... it's fucked. not only would it need seals but the pistons are fucked themselves.

In what way are the pistons 'fucked'? Badly scored? Corroded? Damaged or corroded seal grooves? It's rare for pistons to be fucked without inept mechanic intervention.

Originally Posted by Jerry74

Use heaps of CRC Brakeleen, it evaporates, takes all the muck off with a wipe.

And fucks the rubber seals nicely too.

(not getting at you, just trying to be informative)

If you read the can carefully: "Protect rubber brake components and painted surfaces from overspray" or something to that effect, as I recall. The best way to clean calipers is hot soapy water and a toothbrush. Tedious, but effective and safe.

**Jerry74** · 18th August 2008, 18:46

I was talking about the disc and pads.

Easier to remove it all from the main body of it

**FROSTY:Me** · 18th August 2008, 18:56

shit this is such painful reading.
Call me--bring ya bike here--lets get it sorted.
-I live at work -Literally and Im in Henderson

**racefactory** · 18th August 2008, 21:19

really frosty? you think you can fix the caliper? Well i'm very keen- thanks.

The pistons are fucked in which way? All of what you said - corroded, scored, fucked seals- the works. also because the front of them are ever so slightly deformed apparently. They both do not move by hand. Can't even get it a quarter in with hand force. Jammed solid.

**motorbyclist** · 23rd August 2008, 21:42

ok, thread is too long so i didn't read, but i got the impression no-one aswered the question in a helpful manner

now i do realise you've bought a new one, but now i know why you've done that it's kinda painful. this is literally a handful of $6 seals and some some soapy water (or brakecleen) to fix

and don't be afraid to ask for a hand if you don't know what you're doing. many guys will come round to give you a hand, or just drop by frosty's, OR come to the SMC fix it days that i told you about

Originally Posted by trademe900

Hi all,

First time with all this.

VFR400 NC30- Found my rear wheel wasnt spinning too well and ive found out the rear brake is dragging.

I took the caliper off to inpect.

1. The small pole that the pads slide on was all rusted and gummed up... pads were hard to budge along this slider... i guess that is part of the problem. So should i clean this slider and just regrease it?

do not grease the brakes! clean them and leave them. crc, oil etc etc will stop them functioning and root the seals.

you may put an anticorrosive grease thing (i forget what it's called, but i think it's silicone based?) on the threads to stop it all rusting together

Originally Posted by trademe900

2. While i had it off i decided to inspect the piston and rest of caliper. Protruding part of the pistons are gummed up I saw. So i pumped the rear brake pedal to get the pistons out. Only one came out- the other is still in there and hard to move. How do i get this remaining piston out with no hydraulic pressure left?

stop the free cylinder moving and pump up some pressure. i've had a similar probelm with one of my fronts - had to hold 3 pots back to free the one.

you need to remove all the cylinders and seals, clean whole unit and replace seals. donw

Originally Posted by trademe900

3. Once i have cleaned the pistons, should i grease up the cylinders? What do i do that with?

do NOT grease your brakes!

Originally Posted by trademe900

4. How do i put them back in? Just force them with hands?

force? "reinstall"

yes with hands

Originally Posted by trademe900

5. This caliper didnt seem to have any pad springs like it is supposed to- what does that mean?

pad springs? wtf?

maybe you'll have a scratch pad to make a squeal when pads run low... usually it's been lost though

Originally Posted by trademe900

6. Should the pistons retract back after pressing the brake pedal/be easy to push back or does the force of the brake disk spinning just push the pads/pistons away?

the pressure drops and the pads just lightly brush the disc

Originally Posted by trademe900

7. Once i get it back together- do i just put it back on and fill up the reservoir with brake fluid, and then bleed the system?

yep

Originally Posted by trademe900

8.Anything else that could be contributing to the problem? Shall i throw some grease in the axle and bearing before putting wheel on?

Thanks in advance.

should fix it nicely.

assuming it is the correct grease, yes, bearing like grease and those ones are expensive.

**racefactory** · 23rd August 2008, 22:25

hey man... that would be very helpful but the thing is- i took it to a shop, they said it was totally fucked... piston seized well and truly... piston ends fucked amd corroded, sides corroded. I couldnt even generate any pressure to pump it out of the seizure. I got the impression i should just buy a new caliper since i wouldnt have known how to clean it properly, treat the corrosion etc. Thanks anyway.

After fitting my new brake and adjusting that bloody brake light switch it should be all ready to register and warrant for the road.

**motorbyclist** · 23rd August 2008, 23:42

sweet as then

how much did the new brake cost?

**racefactory** · 24th August 2008, 09:10

175 a. Has to be done i guess.

**geoffm** · 24th August 2008, 09:36

Originally Posted by trademe900

really frosty? you think you can fix the caliper? Well i'm very keen- thanks.

The pistons are fucked in which way? All of what you said - corroded, scored, fucked seals- the works. also because the front of them are ever so slightly deformed apparently. They both do not move by hand. Can't even get it a quarter in with hand force. Jammed solid.

The pistons get rust under the chrome plating and it is all over for them. There are aftermarket alternatives.
Alternaively, do you know of anyone with a lathe (like me for instance...). I made new brake pistons for my RD350LC from stainless steel. Made around 3 pairs from a $20 bar of 316. Might still have some left if you can't get replacements.
Geoff