This fall my brakes started feeling a little mushy, having to pull the lever almost all the way in. I bled the air out of the brake lines and it did good for a couple of months but now I have the same issue again. There is no sign of leakage anywhere on the system. I figured maybe a master cylinder rebuild but the local shop said more than likely need new calipers from his experience. Any ideas on what my first move should be on fixing the brake issue? I have 18k miles on the bike. Still has stock pads and they look good is how babied this bike is.

It's got lower miles on it but it's getting to be quite an old bike. Maybe the rubber parts have deteriorated and clogged up something? Or pistons are sticking? If either of those were the case, I would expect normal pressure in the lever but weak brakes--or else weak lever pressure but the brakes drag.

Seems like there has to be air IN the fluid if the lever is soft but the brakes are grabbing and releasing normally. Sediment or water would not reduce pressure. Sediment clogging might prevent the pressure from getting to the calipers but the lever would feel stiff as ever. Anyway, if you bled the brakes with the lever and fluid came out of all the fittings, there are no clogs.

I bled the air out of the brake lines and it did good for a couple of months but now I have the same issue again.

I would drain the fluid completely. Get rid of everything in there and fill it with fresh fluid, flush and bleed it.

Also, ask the mech what could be wrong with calipers if they work normally when you bleed the system.

Try bleeding the top nipple at the master.

Ok, thanks guys. Going to flush it and put new fluid in next week. Time for a good preventative maintenance on it the bike anyway.

Never heard of caliper failure/replacement on a ZX-14. I think your "mechanic" is trying to sell you some expensive parts you don't need. I know of many who have replaced rotors (multiple times, in the case of stock parts) tried different pads, replaced the stock rubber-sheathed lines with braided stainless, even used expensive, aftermarket master cylinders, but caliper failure is something pretty much in the realm of unicorns and honest politicians.

I think your "mechanic" is trying to sell you some expensive parts you don't need.

I hope the bleeding works. It seems odd that bleeding worked for you but then the problem came back so maybe there is some problem. If there's air getting in, fluid would have had to have come out somehow. My only guess would be there is a tiny leak somewhere where you don't see it (maybe the calipers) that is letting fluid out and air in. Even so, I'd think you would replace some seals or something but not the whole caliper.

Think about it. What could go wrong with the caliper? The only moving parts are the pistons. Maybe new seals sure, but you surely don't need new calipers.

Mad

After you bleed the system and if it goes soft again I would start with rebuild/replace the master cylinder first. Could be fluid leaking past the seals instead of pressurizing the lines and pushing on the pistons.

We'd have 200 caliper threads by now, who's caliper to use, the oil, we'd be all over it. Only guy makes mention and where are the brake caliper threads? I'll smoke what he's having.

I agree, the Nissin Calipers and Nissin master cylinders (same part numbers)
have been around for quite a while and are installed on many bikes over many model years
for like the last decade. Both are a very good components.

I've yet to see or hear of them fail. I've the exact same combo on my zx10 too.

Maybe someone dumped some DOT 5 in there by mistake and messed up the seals?

I took the bike to a reputable shop in Charlotte that does a lot of ZX14 and Busa builds to have it serviced, valves checked, new chain, manual cam tensioner installed and all fluids drained and replaced. Hopefully be good to go after that. He didn't seem to concerned about the brakes. Said, drain it, bleed it and go from there. I figure I would trust him that has been in the business over 30 years than the stealership that has a high turn over rate for mechanics. Hopefully make this bike last til Kawasaki puts out a second gen bike in Candy Thunder Blue then I will be all over it.

By far, I'd trust a shop like that over a dealership. I'm sure they'll track the brake problem down if there is one.

The problem is, dealers don't make much money on sales, they make it on parts and service. Newer bikes are more and more reliable to the point of being bulletpoof, so some dealers make their living employing low-paid, unskilled mechanics and others try to make up for low revenue by blowing smoke and bullshit up unsuspecting customers' skirts with outlandish claims and statements. Neither of these do anything positive for their business images and reputations and as a result, most knowledgeable owners don't trust dealers to take decent care of their machines. If you find a good, honest shop with friendly, knowledgeable employees, throw them all the business you can afford. Those guys need to be encouraged and supported while the others just need to go away.

Well, same issue again. Bike set a month and the front brake is soft. It seems to be getting worse. After dealing with a bunch of other issues caused by what I was told was one of the best bike mechanics around I am going to take it local this time since I am friends with the guy. He was actually booked up but offered to work on it at his house since his shop was full. He suggested to replace the calipers and is what fixed the issue on another ZX14 with the same problem after rebuilding the master did not help. Suggested to use Suzuki calipers because they cost less than the Kawasaki calipers or if I was in it for the long haul to go with Brembo. Seems like just rebuilding what I have would make the most sense. I still have no signs of leaking anywhere. What do you think, rebuid, ebay ZX14 calipers, Suzuki or bite the bullet for Brembo?

If it was me I would rebuild myself first. The major cost is in the big metal parts. Once apart, if the pistons are corroded they can be replaced but I would think the main body would be OK and just the seals need to be replaced. I caveat this by saying if the bike went years without the break fluid replaces then corrosion may have done in the calipers.

I would not have Suzi parts on a Kawi and unless you are racing all the time the Brembo's are a bit overkill, IMO.

* Last updated by: cruderudy on 8/1/2016 @ 10:03 PM *

Agree with rudy. The suz calipers are prolly ok. The MC Kaw uses is what gives it great brakes but I would n't want to change anything else anyway. Brembos are not going to give you any better braking unless you are an expert track rider. Had one member tell me that unless you go way high end (spending about 4K$) on the best Brembo calipers, no performance change at all from stock calipers. We already have the ideal MC and that is what is great about the 14s brakes. ...and that's why busa owners upgrade to ZX-14 MCs.

...but if you have a couple thou you can throw on the bike, those Brembos look sweet!