Front master cylinder change?

[screamingnoob]

hi there my front master cylinder has loads of play and the brake is spongy i have bled the brakes again and they were fine i was watching a guy on youtube who changed his stock front master cylinder to a gsxr-r 600 radial master cylinder and i am thinking off doing the dame has anyone on here had any experiance doing this and is it worth it cheers

[squirrel_hunter]

Depending on the M/C used you may well change the ratios and basically make it worse. Full consideration should always be given to make sure that the M/C and the calipers are compatible. Off the top of my head however I don't know the ratios of the SV calipers against the radial one you are considering.

But...

I would respectfully suggest that you either are not bleeding the brakes properly or you have another issue as replacing a M/C is quite expensive when correctly functioning brakes are adequate.

So what is your exact set up and how are you bleeding the brakes?

[screamingnoob]

its a standard set up and i work in a bike shop on Saturdays and have bled brakes before so i know i'm doing them right because i did them once before and there was loads of air in them so they feel a little better but there not brilliant even one of the mechanic's i work with said they feel ****. do you think it might be the calipers that need a service the bike has done 32000 miles in 3 year and i'm also thinking of putting braided hose lines on to see if that will stop the sponginess a little bit.

[squirrel_hunter]

First off, exactly what model and age is it?

If its done 32k in the last 3 years what sort of maintenance has it had? If the answer there is nothing then there is nothing wrong with servicing the whole brake set up (a long with anything else that has been missed) if you are confident and know what your doing. If not ask. There is also nothing wrong with adding braided lines.

If you work in a bike shop and the mechanics have looked at it what did he suggest? Also are you using the original levers?

[screamingnoob]

Its a 2010 Suzuki sv650s k9 as far as I know and from looking in the service book the bike has had all its service's as the book is stamped up to date, ive only had the bike for 1 year and its had one women owner before me and its got standard levers do you suggest a aftermarket lever?, the guy I spoke to didn't say any thing about what could make it better just that they feel **** the thing is aswell sometimes they feel **** and sometimes they don't which is weird but I think I'll strip the calipers down and clean them up as when I was trying to push one of the pistons back once it took a bit of a struggle to get it back

[squirrel_hunter]

Providing you know what you are doing and are confident then yes give the brakes a full service.

If the service book is up to date then you have to assume that all bits have been done that should have been. However that wouldn't stop me from servicing my own 'new' bike.

Even though you have bleed them doesn't mean to say there is not still air trapped in them. A little trick is to clamp the front brake lever on overnight. This helps to allow air up the system and out of the M/C. And its nice that a mechanic you work with will tell you your brakes aren't very good, but then doesn't offer any advise after that...

As for the levers, no I'm not suggesting that you replace them. There have been many instances of cheap aftermarket levers causing issues. Its good to rule that out. Fault finding should be methodical.

One more thing you say you've previously tried pushing one of the pistons back and found it a struggle. Why may I ask were you doing that?

[screamingnoob]

I had the calipers off because to try give them a good clean without taking the hose's off and my brother pulled the brake lever in whilst wondering round the bike when they were off so the pads were to close together to get the caliper back over the disc so I had to push the pads back but whilst doing this one of the pistons was a real stuggle to get back far enough to beable to get the calipers back on