Brake failure?

[199er]

Evening all,
Been browsing on here since I've owned an sv and I've decided to join and ask for some advice.
I have a 02 model curvy which is standard except one thing, which is good ridge lines.
After they were fitted I rode it and there were no problems, I didn't ride the bike for 2 weeks and when I took it Out again there was no front brake the lever drew all the way in without it stopping the bike.
After telling the mechanic who fitted lines what had happened he bled them for me which sorted the problem.
After leaving the bike for a week and a half the problem has come back no font brake again, could it just be that it needs bleeding again or is it something else?

[Biker Biggles]

Thats certainly not right at all.Take it back to the mechanic and get it looked at

[Fruity-ya-ya]

Thats certainly not right at all.Take it back to the mechanic and get it looked at
+1

And welcome to the org.

[sv_rory]

mine did that, it needed a new master cylinder

[speedyandypandy]

mine did that, it needed a new master cylinder
yes, mc draws air and pumps air into the system, happens more often than you'd think, but changing the whole thing is normally overkill, a service kit from wemoto should sort you out.

[Thunderace]

Yep the piston rubber on your master cylinder has likely split, service kits and new/second hand master cylinders should be roughly the same price on fleabay, I've just fixed same problem on my beasty and the m/c I bought was cheaper than a service kit but only by £4.

[Steve]

yep me to, a master cylinder overhall kit from m&ps fixed it

[199er]

cheers for the advice guys got a service kit on order, rode it today it still brakes well but ive got more pull on the lever but the last time it failed the lever pulled all the way into the throttle and didnt have braking power the disc just slid through the calipers.
No harm in rebuilding the master cylinder though just to be safe.

[speedyandypandy]

Have the calipers ever been serviced? I would do that as well. Great difference.

[sv_rory]

I tried a master cylinder repair kit and it made no difference hence changing the whole master cylinder which was actually cheaper

[Nicky S]

I had this same problem

I changed and serviced every thing ... In the end I needed a new master cyclinder. but they are not cheap £130 I think.

Few things to try first

Get an
rubber band and place this over your leaver and handle bar pulling the lever in. Leave it over night or 24 hours and it should bleed the air into the top of the master cyclinder. Top up fluid.

May work but then again it might only be a quick fix in a week or so you could have no brakes.

Next buy a seal kit for your master cyclinder. Seal and spring that goes around the plunger. Around £30 I think

No joy try

Next top lid and seal plus the 2 screws £20 ..

If you still have the problem check cailpers... New seal kit for the cailpers.

If you still have the problem I'd say it's time for a new master cyclinder.

[Thunderace]

In the end I needed a new master cyclinder. but they are not cheap £130 I think.

Try this if it don't work send it back!

http://www.ebay.co.uk/itm/Suzuki-SV650S-SV650-SV-650-S-02-K2-Front-Brake-Master-Cylinder-/120931501828?pt=UK_Motorcycle_Parts&hash=item1c28144704&_uhb=1#ht_675wt_1037

It's what I did and it worked.:smt040

[199er]

Cheers for the advice, I've got a master cylinder kit on order and booked it in with the garage.
I tried the rubber band trick it didn't make any difference with length of pull I had but when I took the bike it still broke properly, once it's in the garage I'll find out exactly what's wrong. If its a new cylinder then I'll have to buy One can't scrimp on tyres or brakes.

[Nicky S]

Any news on your brakes ???

[199er]

Got home yesterday and dropped the bike off first thing this morning so I'll let you know this avo hoping it's sorted especially with the good weather we've got the weekend.

[199er]

Speedyandypandy was right the calipers needed a strip down and service so they're perfect again now.

[speedyandypandy]

Speedyandypandy was right the calipers needed a strip down and service so they're perfect again now.
ohh I like the sound of that, not me being right offcourse:rolleyes::p but that your brakes are back to normal:D

[monkey]

yes, mc draws air and pumps air into the system, happens more often than you'd think, but changing the whole thing is normally overkill, a service kit from wemoto should sort you out.

How does it do this if there's enough fluid in the reservoir?

[speedyandypandy]

How does it do this if there's enough fluid in the reservoir?
I don't really know the why, but twice over the years I've had fellow club members discover that their mc draws air from somewhere, with fluid level where it should be, and no fluid leak anywhere.
Two of the guys in the supermotard crew has the same bike, with the just about the same setup, quick release fittings on the brakelines, they changed around their mc and they guy with air problem was cured and his mate that had perfect breaks came in after 3 rounds saying "I want my mc back, yours drawing air" I've only taken a part 2-3 different types of mc myself, so I'm no mc expert, but I would hazard a guess at dried up rubber on the part where the hose from the resorvoir goes into, only place with no pressure, maybe it wasn't assembled correctly at one stage? Your guess is as good as mine. maybe debris from a crash? Couldn't be hit in a crash(I think) because of the big handlebar crash protectors thingy.

[monkey]

Must be a leak so slight it doesn't let fluid out but air in.

[speedyandypandy]

Must be a leak so slight it doesn't let fluid out but air in.
could be, to feel the difference after just 2-3 laps it would have to be many small leaks. A light brainstorm while painting woodenmouldings in our hall gave me some more ideas: maybe there is a small suction action going on inside the mc either when pumping or on return, so when hydrostatic pressure is equall there is no leak, but if there is "under" pressure it sucks in air if there was a hole/weak area somewhere. Could well be there was something wrong in the rubber form process for just that part and that it ended up "raw" or poorer quality than it should, maybe the guy should have sent it away to have it tested, but he just fixed it so he could go have fun again the following week.