Best method for bleeding front brake system?

[998420]

I always sucked from the caliper with a big syringe, never heard of the push idea, what is the thinking behind that ? It sounds easier to get air in accidentally like that.

Also, remember to tap your brake lines as you bleed, it can help free up and remove air bubbles sticking to the sides.

[moanthebairns]

I do the cable ties trick. Works well.

[13aines]

mpusch, my stepdad has something similar and while it's easier than without it's never worked that well for me really.

Obscene kindly offered to let me use his compressor and vacuum bleeder, so next weekend I'm going to try to get over his and get it done. Shouldn't take long with his kit!

Thanks for all the responses, looks like i'll reverse fill the system in the future, and if that isn't easy enough i'll buy a vacuum bleeder that doesn't require an air line.

In the meantime, is it worth cable tying the lever overnight? If so just squeeze bloody hard and tie, or just like fairly heaving breaking?

[mpusch]

13aines said:

mpusch, my stepdad has something similar and while it's easier than without it's never worked that well for me really.

Obscene kindly offered to let me use his compressor and vacuum bleeder, so next weekend I'm going to try to get over his and get it done. Shouldn't take long with his kit!

Thanks for all the responses, looks like i'll reverse fill the system in the future, and if that isn't easy enough i'll buy a vacuum bleeder that doesn't require an air line.

In the meantime, is it worth cable tying the lever overnight? If so just squeeze bloody hard and tie, or just like fairly heaving breaking?

Fair enough, definitely do what works for you

That's another question with plenty of opinions. I've done it a couple times when I had a bit of a squishy lever, and I think it helped a bit at least temporarily, but hard to tell if it was just placibo effect. I think nothing will replace doing a full flush and bleed correctly and if you do it right you shouldn't need to zip tie it.

[moanthebairns]

whats the worse that could happen

[theshrew]

Yes it's worth a try as you can get lots of tiny tiny bubbles that take ages to work there way out.

[moanthebairns]

[dern]

You don't need any of these systems on a bike as everything is so close together and the amount of fluid is so small. I use a pressurised system on a car but don't bother because just doing the job takes less time than mucking about with the system. You just need some flexible pipe, a jam jar and a spanner.

[998420]

998420 said:

I always sucked from the caliper with a big syringe, never heard of the push idea, what is the thinking behind that ? It sounds easier to get air in accidentally like that.

Also, remember to tap your brake lines as you bleed, it can help free up and remove air bubbles sticking to the sides.

Nobody? It seems blatantly illogical to push air and crap into the bleed nipped when you can just suck it out...

[mickrick]

Christ on a bike! As dern says, all you need is a spanner, some rubber pipe and a jam jar
Just done both mine about two weeks ago, after fitting new pistons and seals front and rear, and rebuilding the rear master cylinder. Both levers are now rock hard.
So just pushing some new fluid through should be easy peasy. You should do it every year anyway.
Just pull the lever, and undo the nipple, then lock it off before you get to the end of the travel. Repeat, as often as necessary. Keep the reservoir topped up as you go.
No need for all this penis enlarger pump malarkey!

[moanthebairns]

You try getting fluid into 6 pot tokios when you've rebuilt them with a jam jar

My God. What a ball ache

[mickrick]

Mine are 4 pot Nissin, wasn't too bad. Just need a bit of patience is all.

[13aines]

I know you can do it with less kit but in the past I've had awful difficulties getting a firm lever using traditional methods but then this has generally been after fitting new lines and starting with an empty system.

I'm going to obscenes gaff tomorrow to utilise his air line. I may as well

Next time I'll persevere with traditional methods or use a syringe.

Thanks all.

[mickrick]

Well mine were totally dry. I fitted new lines, rebuilt the calipers, and the rear master cylinder. So just changing it should be a doddle.
If you have a spongy lever you still have air in it. Just keep bleeding until you have a hard lever.
The secret is to open the nipple while you have the lever squeezed, and to nip the nipple up before you get to the end of the stroke.

[vrod]

Another one for the syringe and tube method. Used it on mine and it worked a treat.

[Biker's Nemesis]

Don't forget to bleed at the master cylinder if you still have a spongy lever after numerous attempts without success.

[DJP]

Mr OCD said:

Use a MityVac... best thing ever for bleeding brakes

This^^.

[13aines]

Well I did it this morning with Obscene, and his air line and vacuum bleeder. Blimey it was easy! Thanks Obscene.

Was astonished by the amount of air bubbles (more air than fluid!) when we initially started drawing through the fluid on the LHS caliper. We finished up with both calipers drawing some very small air bubbles close together and the master cylinder not too bad. After a couple of pumps using the traditional bleeding method the line was clear of air. Back was really easy, and feels much firmer actually, surprisingly very noticeable.

The front seems much more effective but the lever still doesn't feel as rock hard as my ancient old Diversion so I've cable tied the lever back for the night. Even if the lever still doesn't feel rock hard the fresh fluid and bleed has certainly made the brakes much more effective. Looking forward to trying them out properly on a dry day.

[dern]

I found that with any method of drawing the fluid out it's easy to confuse air in the system with air being drawn around the bleed nipple if you've undone it far enough. It's easier to pull air in around it than push the brake fluid out past the thread.