Saturday, 7 November 2009

Sticking piston due to dust seal in Brembo Gold line 4 pot calipers

5165 Series: P3034
(2 x 30mm + 2 x 34mm Pistons) Cast Aluminum Body

20.5165.50* LH GOLD LINE snap-type pads pin
20.5165.58 LH GOLD LINE cotter-clip pads pin with anti-rattle plate
20.5165.60* RH GOLD LINE snap-type pin
20.5165.68 RH GOLD LINE cotter-clip pin/ anti-rattle plate

OE front application on most current Bimota, Ducati, Guzzi, Laverda, and other European makes from ‘93 to present, as well as standard issue in brembo brake kits.

GP 32-36 Front Caliper
(2 x 30mm + 2 x 34mm Pistons) Billet Aluminum Body

After fitting new sintered (07bb15sa) pads to my Brembo gold line 4 pot calipers and having driven about 100 miles, I noticed there was a resistance to move the bike slightly. I decided to lift the front wheel with stands and found that the front wheel was slightly binding as it turned. I then loosened the left hand brembo caliper with the two 8mm allen screws. As soon as the left hand side was removed the wheel rotated freely. I then read that the front wheel should be bounced with the nuts loose then tightened in a certain sequence and then re-tightened to correct torque. With the wheel on the ground and loosened I bounced the wheel tightened the pinch nuts, then tightened the front wheel and checked again with wheel in the air. It was still binding, I took the pads out of the left hand caliper and pulled the front brake lever. I noticed that one of the larger pistons was slow to move out. I then put a screwdriver handle in between the smaller pistons and a pair of mole grips on the opposite large piston. I managed to push the piston out enough with the lever, then pull it out the final few milimeters with just my hands rocking the piston from side to side. The piston was clean and undamaged. I cleaned the dust seal and the main seal. Then thought i should remove them just in case. I have had bikes in the past where water has setteled behind the seals causing corrosion and pushed the seals out. I removed the main seal, cleaned and found no dirt. I put the piston back in but it was extremely tight. Then taking the piston out I decided to take the dust seal out also. It had a indent on the inside and when looking at the indent in the calpier body it seemed to be a locating plug. When I checked with a small screwdriver with a smaller blade to fit the gap. It scraped off and was a build up of dirt. I cleaned it by soaking in brake fluid and scraping with tissue until it softened enough to remove.

I replaced the seals after ensuring all dirt was removed, covered them in brake fluid. The piston pushed back in easily and realised I had found out why the brakes had not returned to their normal play. Now when pulling in the lever there was very little play. Spinning the wheel there was no binding from the brakes. At last working as they should.

Reminds me of a few things to follow.

Take time to clean and strip parts

Some times it is easier to take longer and remove items then try the quick way in situate.

Look in the forums for help and advice. Ask mechanics for advice. If you have a good friend like Pat who was my old supervisor when I was a mechanic years ago. He told me the probable cause straight away....

So thanks to Pat

Bike is back on the road and nearly 29 thousand miles covered now

Sunday, 1 November 2009

front brake light switch Ducati 916

In the past the front brake switch stopped working and I noticed the ball bearing or rubber stopper that fits in the brake had dropped out. After replacing this part. It has been working for a while but checking the lights when I pulled up at home recently I noticed the back brake light was on permanently. Found it was the front switch sticking, as you can see it has now been taken off. the faulty switch when pushed in stayed in. It is a sealed unit which rs supply. I will have to source a replacement switch.