Brake problems on 97 VFR750

Hi,
first post but been reading the site to diagnose my RR probelm on my 97 VFR - 15,000 klms.

Latest problem is a front brake leverl that comes to the bar. When I got the bike the fluids look original so I used a mytivac to change the fluid. For the next 500 Ks the lever got closer and closer to the bar. So I re-bleed the brakes the old school way. Didn't see any air bubbles and the lever seemed to have better feel. Still only about 2 cm from he the bar but. Went for a ride today for about 400k and the lever is now back to the bar - bit scarry for the last 100k! No signs of leaks. Any ideas on what to check next and how to do that appreciated.

Thx
Bruce

 

Firstly welcome to the MadHouse :welcome: Bruce!

When you get a chance the folks on here would love to see some photos of your VFR. Perhaps update your profile to include your location and bike specs so if you hit problems its just possible a nearby VFRW member would be willing to swing by and offer advice/assistance. We have a fair few from Oz - so you never know you may find some folks to ride with.

As for the brakes on the 750 they should be fairly standard design without any of the complexities of ABS systems and linked brakes which can make bleeding a real chore on later gens. Start with the basics. You have checked the fluid you used was from a sealed container of suitable DOT 4 and that the reservoir level has not dropped since you changed the fluid.

(If initially the lever felt squishy then you probably had air trapped in the system and need to continue bleeding the system until it firms up. I don't know the ezibleed system you refer to, but I assume if you use it properly it should work fine. If you are not sure, the safe bet is to read and follow the system described in the service manual.)

So working on the assumption that after you swapped the fluid, the lever gave a firm and positive application (ie not squishy) but since then the bite point has progressively retreated towards the bar - this is a classic sign of the piston seal failing in the lever allowing fluid to flow past - so no visible leaks but it results in a slowly lower bite point.

I doubt it will be down to a problem with the calliper if you did not disturb it at the time. If however you swapped out the pads then its definitely worth checking closely. Also worth a close visual inspection of the lines looking for any sign of swelling and also focusing on the banjo joint seals just in case the line is close to failure.

If you conclude it is the lever , rather than fit a service kit to a 16 years old lever (which will probably be the cheapest fix), you may want to compare the price of replacing the whole lever, especially if until recently it was still being used with the original fluid. OK the bike has not done many miles but fluids age and as they decay can drop debris and its possible the lever bore has already been scored by debris and you may never be able to get a reliable seal.

When it comes to motorbike brakes or tyres(tires) they are not things to mess with lightly or economise. If you are reasonably mechanically competent and follow the service manual you should be able to fix this yourself.

Good luck and give us an update.




SkiMad

 

Hi Skimad,

thanks for the welcome. I will update my prfoile in the next couple of days.

What you say all makes sense. I will check the price of a new MC and I have already checked the price of the kit on-line.

I am confident that the bleeding process has gone as expected so, I had thought the 2 things you mentioned would be the likely culprits.

As to braid steel lines, can anyone in AU tell me if it's legal to put Galfer lines on? I thought I had read somewhere that there was problems with ADR if you fitted something like that.

Thanks again,
Bruce