Brake trouble

[racefactory]

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?

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?

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

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

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

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?

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?

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.

[MSTRS:Me]

Why are you asking this again (even if it is in another thread)? RT has given you good advice. Don't piss about with something so important, when you obviously aren't sure what you are doing. Take it to someone who does.

[racefactory]

hi there.. I am simply moving it to the right forum. Maybe more brake people can help. It is not to do with chain/wheel.

I'm doing it myself. You have to learn somehow. I have taken the interest to fix something that another person could have quite easily left be until their wheel seized or something. If i want to fix it- let me.

As a student i don't have too much $ to splash about and i have already decided to pay someone to do my forks for me. Please understand.

Cheers.

[hayd3n]

brakes are one thing you dont fuck round with!!!! if you dont know what your doin get some one who does who can help you i first had a m8 who owns a 4wd help me .
disk brakes are all very similar
some times you thinks its all bleed and it isint

[MSTRS:Me]

Oh I understand all right. Lack of funds is a great motivator in doing things for yourself. What I am saying, and RT has said, is don't 'repair' stuff that is critical when you have little or no understanding of what you are doing. If you 'get it working' but have somehow made a mistake or missed something that shows up at an awkward moment, what then?

[xwhatsit]

Hey man,

When I did mine I asked questions on here, used my manual, and also found this site to be very helpful: http://www.dansmc.com/hydraulics.htm

I only had one piston, but on the newer type callipers with twin pistons it talks about using a C-clamp as you go -- let one pop out a bit, then put the C-clamp on it and keep pumping until the other one comes out a bit, then shift the C-clamp again. Of course, you've already popped out one piston. I may be overlooking the obvious here, but can't you put the other piston back in, let it seal, put a C-clamp on it, pump it up with brake fluid until the other piston pops out too?

O-rings can be suprisingly expensive for bikes. Somebody on here (pretty sure it was Imdying) gave me the tip of using car brake seals with the same diameter. Tuppence in comparison. I ended up getting a proper seal, as it was cheap (old, common calliper to a lot of Honda models), but if it is a lot, perhaps something to investigate.

[racefactory]

Yes you are both quite right...

But it is so tempting to do when you have some people saying... hey brake calipers are dead easy!

[fatzx10r]

Oh I understand all right. Lack of funds is a great motivator in doing things for yourself. What I am saying, and RT has said, is don't 'repair' stuff that is critical when you have little or no understanding of what you are doing. If you 'get it working' but have somehow made a mistake or missed something that shows up at an awkward moment, what then?

what he said, get it wrong and you could be

[awayatc]

Clean all the parts properly....
Piston should get back in without to much trouble.....
Block it (bit of wood or so)and apply pressure on brake, the other piston should pop out......
Clean,clean.clean...(brakecleaner or very fine metal scouring pads with bit of brakefluid....)

Everything should reassemble, and best to replace all brake fluid with the correct grade new fluid
...which needs bleeding indeed
No grease.....
Pistons will retract to their correct position automaticly...

Not sure what you mean with pad springs missing.....but your dealer will have detailed drawings on computer with all the parts required.....rubber boots etc.

Good luck, and good on ya for fixing it

[hayd3n]

Yes you are both quite right...

But it is so tempting to do when you have some people saying... hey brake calipers are dead easy!

yeah they are easy once you get use to it just like anything really

[racefactory]

Hey man,

When I did mine I asked questions on here, used my manual, and also found this site to be very helpful: http://www.dansmc.com/hydraulics.htm

I only had one piston, but on the newer type callipers with twin pistons it talks about using a C-clamp as you go -- let one pop out a bit, then put the C-clamp on it and keep pumping until the other one comes out a bit, then shift the C-clamp again. Of course, you've already popped out one piston. I may be overlooking the obvious here, but can't you put the other piston back in, let it seal, put a C-clamp on it, pump it up with brake fluid until the other piston pops out too?

O-rings can be suprisingly expensive for bikes. Somebody on here (pretty sure it was Imdying) gave me the tip of using car brake seals with the same diameter. Tuppence in comparison. I ended up getting a proper seal, as it was cheap (old, common calliper to a lot of Honda models), but if it is a lot, perhaps something to investigate.

thanks so much- that link has pretty much everything! awayatc- thanks also.

I will try this and see if i get anywhere... if not it will have to go to the shop.

One thing i do need an answer to though is what if my caliper has no pad springs??

[racefactory]

Also, it's hard to tell if it's the caliper or not... but my right front disk has a bit of fluid on it. No fluid is coming from the hose as far as i can see. Now i'm not sure if it is because my right fork seal is leaking oil too, and might be dripping down to the brakes... it's damn hard to see though.

Just incase... and until i get round to inspecting the front brakes. what's usually the culprit for leaking caliper? Is it a blown piston seal?

[awayatc]

You mean like a thin metal backing plate on the pads....?
Everything is available ex dealer.....especialy since same brakes are used on variety of bikes.
After market parts available for most makes as well....
Bike wreckers......

[MSTRS:Me]

That's easy...a leaking fork seal will allow oil to get all over the place. The fluid is greasy to the touch. And a leaking brake system will get fluid all over the place. The fluid is greasy to the touch.
Spot the difference?
Get someone who knows what they are doing/looking at to fix it.

[racefactory]

yes thats what i mean. The thin metal plates.

come on mstrs- just go ride your gsxr mate, don't worry about it i'll get it fixed one way or another. one thing is for sure though... im trying first.

Does anyone by chance know what other bikes share these same rear Nissin brakes on a Honda VFR400 NC30?