New Paso owner with questions

[paso907]

I recently purchased a 92 907 I.E. including its shop manual. I have very little experience with anything newer than a 1985 motorcycle.

There are 2 problems with the machine that prevent it from being almost perfect.
1: Even after bleeding the front brakes, after a few days I have to loosen the bleeder valve and rebleed the front brakes because the calipers lock closed overnight. This motorcycle has braided steel lines and is otherwise stock brakes.
2: When I depress the front brake lever the brake light works, when I try the foot pedal I get no brake light. I tried reversing the connector, making sure the rubber boots are secure. I did find a connector not in use behind the front fairing but have yet to trace it fully. I connected the two connectors to a test circuit but got nothing from it making me thing the switch on the pedal brake is fine.
I don't know where to start, the fuses are fine and everything is dry. The machine came back from the shop in April like this and I have since moved. I am reluctant to send the bike into the shop for what is probly a very minor fix.

Any help would be greatly appreciate. I did read the bleeding front brake problem already and tried that.

Paso 907

[qldman36]

Rear brake is totaly seperate system. Rear brake switch is at top of rear master cylinder. Many Suzuki's use the same switch and lot less $'s. Make sure get long style to match banjo bolt.

[paso907]

I appreciate your help with this. Owning a Ducati since 1990 has been a dream of mine and of course I only drove 2,500 miles in the worst weather in 200 yrs to get it. (will not be a repeat for sure)

[pencilbeam]

Unless your disks are warped, sounds like simple pressure build up in the front brakes. I had my rear brakes lock up on me while riding not long ago and actually killed the motor until I pulled the clutch in. Had to release the bleeder slightly just to get the rear wheel to move. Do both calipers lock or just one? Maybe time for a rebuild kit or possibly your master cylinder has a little dirt in it. common on a 15 year old bike. A little dirt goes a long way in blocking those tiny holes in your m/c. I would bleed the brakes again, this time all the way till almost dry then clean out your master cylinder. Use a magnifier to check blockages. Then replace with new fluid and make sure not to overfill. Good luck. Sometimes the calipers are just shot...

[paso907]

I had told the shop that both were locking on me and that I thought it was holding too much pressure or a pressure build up. Sounds like thats the right track. I will get new fluid and try myself to fix the problem. If it persists I'll have to either rebuild or take to the shop. But it happens when its sitting and not being ridden.

Paso 907

[du907]

Since I love working on my paso, I would take the calipers off, remove the dust boots and clean out the dirt, grime, around the calipers pistons, take them out and clean everything up, if there is rust or just dirt, use some fine emery cloth to sand/buff off the dirt. Also do the same with the master cylinder. Take it apart, clean everything up, remove rust, lubricate everything. Also on the master cylinder, when you take the rectangular top off, take the sealing rubber, air space compensator off and you will notice some channels that let air into the cylinder to balance out the space in the cylinder when the fluid moves. These passages or grooves are on the back of the cover. These passages get crudd in them and prevent air from getting in and a vacum can develop.
good luck
du907

[delagem]

Well, if your calipers are locking on, then you've got your lever adjusted too far in. Very common with rear brake master cyl's, too. I did it to mine once!

There is a port in the master cylinder that allows the presure to equalize from the line and caliper to the reservoir. If the actuator screw is adjusted too far in, this port is obscured, and any pressure buildup, from temp changes or whatever, locks the calipers.

Back off on the adjuster screw on the lever a few turns, so that there is a very small amount of play in the lever before it begins to actuate the master cylinder.

[DesmoDog]

Well, if your calipers are locking on, then you've got your lever adjusted too far in. Very common with rear brake master cyl's, too. I did it to mine once!

There is a port in the master cylinder that allows the presure to equalize from the line and caliper to the reservoir. If the actuator screw is adjusted too far in, this port is obscured, and any pressure buildup, from temp changes or whatever, locks the calipers.

Back off on the adjuster screw on the lever a few turns, so that there is a very small amount of play in the lever before it begins to actuate the master cylinder.

Count me in as another "been there, done that" person...

In my case it was the front brakes. I turned a corner, hit the gas, and wondered why the bike wasn't accelerating very fast... figured out what was going on before the wheel locked.

It's very important to have some play in the lever...

[paso907]

I had to back out the adjuster all the way almost and now it hasn't locked or siezed for 2 days.
This kinda forum is one reason I chose the bike I did.

Paso907

[delagem]

Ok, great! Now lets tackle the brake light problem.

Have you jumped the two wires to the sensor, using a short piece of wire or a paperclip? Try this, and see if the brake light comes on. If it does, then the switch is probably bad.

To test the switch, get a cheap voltmeter that checks continuity. I like the ones that beep when they find continuity, so I don't have to be looking at the meter. But any meter that checks resistance will work.

First touch the leads together, and see what the meter does to indicate zero resistane or continuity. Then, put the meter leads on the two terminals of the switch, and, using a third hand (ha!) push the brake pedal. If the meter beeps or goes to "0" resistance, the switch is good. If not, there's your problem.

If shorting the wires with a paperclip doesn't work, then we've got some more digging to do...

[paso907]

I jumpered the wiring and the brake light did work, so it seems its in the switch. Do I just remove the top part or the entire arm. My shop manual shows the switch as under the arm.

Paso907

[delagem]

Hmm, someone with a 907 is going to have to help here. My 750 has a hydraulic switch, replaces the banjo bolt. All my other Duc's use a microswitch. Both are easy to replace, but with the banjo type you will have to bleed the brake after you replace the switch.

I would still borrow a meter and test the switch before , the switch may be good and you just had a bad contact on one of the wires. Worth a try, at least.

If you need a banjo bolt type pressure switch, visit any bike dealer, and have them look up K&S in the Parts Unlimited catalog, that's the cheapest I've seen that style switch. I don't know what Ducati asks for that switch, but I can guess! Usually 2x reasonable, + $10...

[drsalsa@mac.com]

I went to the Parts Unlimited site to search for a replacement Banjo bolt for my rear brakes. Thanks a lot for the tip. Can anyone help me with figuring out which of the many Banjo Bolts available I need for my 907?

My mechanic told me I need to replace mine, but they are no longer available through Ducati.

[Tigger]

Hi

I had he rear brake light switch go on my 907 and went looking for a replacement. This was a pressure activated switch and as the system is brembo, is still used on a very regular basis by racers and track day enthusiasts using a data logging system on their machines. By the way, do not forget to get a couple of new copper washers as well before you fit it!

Try some of your local racing shops.

I managed to pick one up for relatively cheap money from one of these suppliers.

Hope you get it fixed soon.