braided lines and brake bleeding....

[timbo1150]

any help or advice would be very welcome right now!
i have just fitted new goodridge braided lines on the
front brake of my 1150 (non abs). all gone rather
well in terms of fitting the hoses etc but i cannot get
the new lines to 'pressurise' at all.
i have been using a kit with bleed tube/non return line/
bottle.
but i only seem to be getting dribbles through the nipple
(as it were) - and still no pressure....
what the hell am i doing wrong???
heeellllpp?!

thanks
tim

 

[pragmatix]

Do not open the bleed nipple to far a quarter turn is enough. Try tapeing the brake lever back to the bars overnight, this allows the air bubbles to travel back up to the master cylinder and could help.

Pete A

 

[Strangelove]

Had a similar problem with a Z1 Kwak and I had to bleed the system at each union joint from the reservoir down to the caliper.
ie. slacken each joint, pump until the air escaping stops and tighten again. It then bled as normal at the nipple.

I would try pragmatix's suggestion first though as my suggestion means that you have to keep an eye on the fluid leaking out around the upper joins to prevent it lifting the paint. (just to add to the stress of the whole situation!)

 

[cookie]

as you pull in the brake lever, release the bleed nipple (just a bit). close nipple as you reach end of stroke. don't release lever until nipple is closed.

repeat ad infinitum. it will work in the end.

never had a bleed tube with valve that worked on a bike system. i don't think bike master cylinders move enough fluid.

depending on location of bleed nipple, you may have to remove calliper after initial bleed so as nipple is highest point & repeat. can't picture 1150 caliper. unlikely though.

 

[Dave Hall]

You might have an air lock in the master cyclinder, it happens sometimes when you drain the system. A vacuum bleeder like a mityvac would sort it for you or one of those pressure bleeders like Gunson used to make.

 

[The Mechanic]

Right then brake bleeding.....

How to bleed brakes.

1. Place a goodly sized piece of rag under and around the brake master cylinder fluid reservoir, you will need to leave the top off.
BE CAREFUL THAT NO FLUID BUBBLES/ BLOWS BACK OUT FROM THE RESERVOIR.

2. Have a good supply of fresh DOT4 specification brake fluid easily to hand.

3. You will need a glass or clear plastic jar/bottle (mineral water bottle is good).

4. A length of (preferably clear) plastic tubing (Halfords/B&Qetc.)
This tubing needs to be a nice tight fit over the bleed nippple and it needs to be about 12inches in length minimum.

5. Pour a small quantity of new brake fluid into the clear bottle (now known as your 'bleeding' bottle).

6. Put one end of the hose into the bottle and make sure it reaches far enough into the bottle to enter the fluid you poured in
just submerged. you may want to secure the pipe to the bottle (I bore a hole in the bottle lid so that the pipe is atight fit, I then make another hole in the lid to allow air in and out).

7. Now top up the fluid reservoir and push the bleeding pipe onto the bleed nipple. You may want to put a ring spanner onto the nipple before fitting the bleed pipe to allow open and closing to be made less fiddly.

8. Gently apply pressure to the brake lever a few times, now wait a few moments.

9. Open the bleed nipple about 1/4 to 1/2 a turn, now squeeze the brake lever back to the handlebar, HOLD IT THERE and tighten the bleed nipple.

10. Repeat this operation at least 6 times, always keeping an eye on the reservoir fluid level. DO NOT LET IT GO DOWN TO FAR.

11. When you can see no more air bubbles in the clear pipe or entering the bleed bottle from the bleed pipe you are almost done.

12. With the nipple secure and the reservoir topped up you should now be able to squeeze the brake lever and feel a solid lever.

If you cannot achieve a good feel using this method then you may have to bleed each (braided hose section individually, MESSY.

Alternatively as already suggested use a Mytivac, this sucks the fluid and air by drawing the fluid out through nipple rather than being forced out by your pumping action.

Finally if the brake lever feels solid, hold the lever under pressure over night (12 hours) using strong elastic or sliced innner tube bands or cable ties. This will cause any remaining tiny air bubbles to find their way back up into the resevoir.

NOTE: Brake fluid is Hygroscopic, this means it absorbs (readily) moisture from the atmosphere so it should not be exposed too long top the air/atmosphere. Also harms paint RAPIDLY.

DO NOT SHAKE THE brake fluid container as this aerates the fluid.
DO NOT RE-USE ANY FLUID THAT WAS PART OF THE BLEEDING PROCESS.

Good luck, hope this helps you out.

 

[cookie]

cheapo gunson bleeder works great for doing cars on your own & guzzi linked systems.

2 problems:

1. the supplied master cylinder caps rarely fit any bikes. does fit guzzi foot cylinder.

2. the flippin' thing is affected quite badly by...er...brake fluid, so has to be cleaned out thoroughly after use.

 

[GEOFFREY DEACON]

Most of the above methods work fine, but other ways are,?
Try injecting fresh fluid through a seringe up from the bleed nipple to push the air up and out,(beware ,can be messy),
Or secure the nipples,fill the resevior then lightly apply a little pressure to the lever (no more than a few millimeters-mini pumps so to speek) This allows the fluid to travel down around the bubbles of air and raising them to the top,=little bubbles will appear if working??, do this untill air stops then bleed normally to finish.

 

[littleredrooster]

Foolproof Way!

Instead of trying to use the Master Cylinder to pump the fluid down the pipes, use a syringe to blow it back UP from the bleed nipple. Start with the master cylinder empty (and brake pads pushed back into the caliper) and suck the fluid into a large syringe (with a length of plastic pipe on its end). Open the bleed nipple, attach the syringe and CAREFULLY squeeze the fluid up into the system until it appears about quarter of the way up in the master cylinder. Close nipple. Repeat for other side; bingo! job done. Solid lever. Big advantage of this method is that the air is travelling in the direction it wants to go - UP!

Done 2 in the last 3 weeks like this - 10 minutes maximum.

 

[littleredrooster]

Sorry, Geoffrey - we were obviously typing the same thing at the same time!!!

 

[timbo1150]

thanks all.
will try again with some of the suggestions. think i may
have been loosening the nipple too much. if no joy i'll
try a mityvac (?) or something.
will let you know.
cheers
tim

 

[MasterDabber]

I've used the syringe method suggested by littleredrooster and Geoffrey on a particularly recalcitrant Beta trials bike (very small brake pistons) and found it fixed the problem.

 

[Steve]

Re: Foolproof Way!

Instead of trying to use the Master Cylinder to pump the fluid down the pipes, use a syringe to blow it back UP from the bleed nipple.

Excellent idea! Now:

1. How large a syringe, and suggested places for purchase of said item?

2. Can you use the above method when replacing the fluid annually, and does it also replace the fluid in the ABS unit?

 

[cookie]

you can buy the syringes from specialist motor tool dealers for this very purpose.

in my experience this method does not always work & you have to clean them afterwards.

on a simple brake system i would first use the simple bleeding system detailed so lovingly by the mechanic.

 

[timbo1150]

result!

after several hours fannying around with the tube c/w
one way valve i just chopped it off and used the bottle/cap/
fluid method. job done in 5 mins. bloody bleed kit.
many thanks. you saved me a lot of time and anguish.
happy man now
cheers
tim

 

[littleredrooster]

Re: Re: Foolproof Way!

Excellent idea! Now:

1. How large a syringe, and suggested places for purchase of said item?

Mine is 60ml. Find someone who works in the NHS! (Matron.............MATRON!)

2. Can you use the above method when replacing the fluid annually, and does it also replace the fluid in the ABS unit?

Yup - pump the system dry first, then blow it back with the syringe. When you come to refill the syringe, don't forget to close the nipple on the 'pumping' stroke of the syringe in order not to allow any air to get in; also, when refilling the syringe, hold it upright after filling and get rid of all traces of air from the plastic pipe. That's sometimes the difficult bit!

N.B. Plastic pipe needs to be a close fit on the nipple so's it doesn't get air in.