Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Ducati 996 front brake locked up?

[Ray]

I have seen a pattern lever cause a front brake to lock as well, on an R1 though.

Can't really see "wrong" fluid causing a problem severe enough to lock a wheel.

I would say you have done pretty well to get the dealer to repair the bike.

If you don't have all the parts that were on the bike at the time of the crash you are going to have trouble proving anything.

Had a problem with a CBR6 with the rear brake caliper falling off immediately after a service, the dealer apologised, supplied a new bolt taken off a bike in the showroom to replace the one that fell off but when I mentioned the paint that had been chipped off the rear wheel as the caliper flapped about they just gave me a tin of paint to sort it out myself!

Ray

[steveg]

Original brake lever is still on the bike, or would this be changed when they replaced front master cylinder. How do i contact the webteam?
M&S(dealer) were not going to pay originally for the damage to the bike(£1500.00), because the test rider could not recreate the locking problem. The day before i was due to pick up the bike, and pay the dosh, they phoned me and told me that their test rider had now in fact experianced the front end locking up (he didnt come off though). It was then and only then that they believed my original explanation, paid for the damage and replaced my 996s front brake master cylinder with a new one from a 998?? admitting that the master cylinder was at fault and that they were sending the offending part to ducati uk. for examination. - and so it goes on.

[chris.p]

Well that is a partial success, hope you get it fully sorted, I think a full written apoligy, bike paid for & leathers etc, plus expensis.

Chris.

[Mark853]

Think i will stay clear of that bike shop!

Name and shame thats what they need.

It's about time these people realise without us they would not have a shop!

I would go to traiding standards defo they will help you to get a fair result.

All the best

Mark

[Edited on 6-2-2004 by Mark853]

[ducv2]

Would that be M&S in Westgate Road??

[Shazaam!]

First, let me say that there’s no such thing as inferior brake fluid. All brake fluids sold today meet one of the DOT specifications, so no matter which one you use, it’ll work fine. Even if you use fluid from a unsealed container, the worst thing that can happen is that the fluid absorbs moisture and will boil if it gets to 300ºF or so. The same thing happens if you don't change your brake fluid once a year or so. The absorbed moisture in the fluid will, however, eventually corrode expensive brake bits over time.

In fact you could put straight water in there and it would work, it would just boil at a lower temperature (212ºF.)

DOT 3 and DOT 4 fluids are compatible with DOT 5.1 - but are not compatible with silicone-based DOT 5. DOT 5 brake fluid is purposely dyed purple to warn against accidental mixing, so you should be able to tell right away if someone added any purple fluid. Another way you can tell is that the DOT 5 fluid will coagulate in the reservoir when it’s added to any of the others.

One concern is that DOT 5 does not absorb water, so any moisture in the hydraulic system will "puddle" in one place. This can cause localized corrosion in the hydraulics.

Also, Brembo products are said to use natural-rubber base seals that are incompatible with DOT 5 silicone-based brake fluids, and there were reports of DOT 5 causing premature failure of rubber brake parts with early DOT 5 formulations. This was found to be due to improper addition of swelling agents and reportedly has been fixed in current formulations.

However, nothing discussed above will lead to brake lock-up. The worst thing that can happen is that you start to have piston retraction problems so the pads drag continuously on the rotor. If the pads drag, the calipers and rotor can get pretty hot as you’d expect. But again, there’s no way that this will result in a lock-up condition.

So when they say they think that it’s a brake fluid or a master cylinder problem, they’re really saying that they just don’t know.

Two possibilities come to mind:

The first is that they failed to assemble the brake mechanicals properly during a recent service, they saw evidence of this, and decided to pay for the repairs (without admitting fault and incurring only limited liability.) I once had a situation where the owner of a Ducati dealership forgot to tighten down the four pinch bolt holding down my front axle, so believe me mistakes happen. If something was loose when it left the dealer, a mechanical interference problem in a left hander (not necessarily right away) is one way that the front wheel would abruptly stop turning.

The other possibility is just bad luck. A piece of metal in the road could get kicked-up and lodge between a rotating and stationary brake (or suspension) part. A small bolt caught in one of the rotor’s cooling holes, for example, will stop the wheel quickly enough to cause you to loose traction, shear off, and leave you wondering what happened.

Since you don’t know what really happened, my suggestion to you is this: Let it pass. There’ll come a time when you may need help from this dealer again. In my case, I went back to the owner (remember he was the one who made the mistake), took him aside and explained his mistake and (suggested) the wisdom in having the shop’s work double-checked when there were obvious safety-related and liability issues. The next time my bike was serviced, I was treated like royalty.

[stimpy]

Hi Steveg,

Had the same problem with a badly adjusted lever a long while back. If they replaced cylinder but not the lever the problem would get transfered. Would be very suprised to find any brake fluid to be the problem. Besides it's not your problem even if it was possible. If it was me I would definetly carry on pursuing this. You would see some pretty major damage if a lump of metal had jumped in your wheel, disk etc, big enough to cause a large braking action. Missing wheel spokes or exploded disks should give this away. Perhaps you could get an independent motorcycle dealer to pressurise the system in reverse and push fluid from the caliper back into the mastercyl resevoir. Check the flow rate. Now remove the lever and see if the flow increases. If it does then the lever is wrongly adjusted. Don't change it as this is your evidence. Good luck mate.

Alternatley give your lever to a "mate", go for a nice long ride, if he craches you know what the problem was.......