Pressure/vacuum/gravity bleeding

[kerryg]

I spent hours last night trying to bleed my brakes with a bit of tubing and a jar of fluid as per the normal way and and the **&%$ing things just won't firm up.....I've left it with the lever strapped in the fully compresed position and hope to beat the bugger tonight. But there must be a better way. Has anyone had any experience with pressure bleeding or vacuum bleeding that doesn't require a big investment in gear to do it?? I'd love to know if someone has put together an effective vacuum or pressure bleeding kit from simple and cheap items. Anyone?

[riffer]

Try "cracking" the joint on the master cylinder. Sometimes it gets trapped up there.

[kerryg]

Try "cracking" the joint on the master cylinder. Sometimes it gets trapped up there.

Yeah I've tried that, at the master cylinder and at the callipers, and tapped the lines,and checked for leaks at the junctions but no joy so far. I'm sure if I persist long enough I'll get there...I'd just like to find a quicker way, given that I had a bad experience with seized brakes recently that has educated me about the necessity for preventive maintenance (i e flushing the brake system) regularly

[sedge]

I bought a one way bleeding kit thing from Repco I think, you crack the bleeder and pump six times, do up the nipple, crank 6 times and repeat until firm, works really well for most things...

GSXR didn't get on with it too well tho ? needed to crack the nipple on the braided lines at the top a bit and it got kind of messy.

Sedge.

[F5 Dave]

You are perhaps talking about Mityvac? Rip-co are the agents some people swear by them. I considered getting one, but thought, well what are they doing?

What does it actually do I asks meself? Surely just forces fluid the other way through the system. In this case it would appear once you have the brakes bleed to the point you have then you could just prise the pads away from each other to pressurise the system forcing the fluid back to the MC. With the calliper off you could place it in another position so as to move some trapped bubbles & prise the pads apart again & pump closed. Move to another position & repeat. Do other side.

With my race bike as the MC is at a crazy angle it helps to either lean the bike over against a wall so the MC is flat (helps move any bubbles that may be trapped there & easier to add fluid).

In the bad old pre GSXR days; Suzis used to have anti-dive mechanisms that created extra lever play, they were always fun. If your system was adjusted previously with not enough lever play then it will feel sloppy now. Have you got the original lines on it? They will be well past their best by date now & be as baggy as MC Hammer’s pantaloons.

[kerryg]

I bought a one way bleeding kit thing from Repco I think, you crack the bleeder and pump six times, do up the nipple, crank 6 times and repeat until firm, works really well for most things...

GSXR didn't get on with it too well tho ? needed to crack the nipple on the braided lines at the top a bit and it got kind of messy.

Sedge.

Sedge

Thanks for that. I'll check out Repco tonight

[Motu]

I don't like vacuum bleeders,they can suck air into the system,that's the stuff you are trying to get out!They can collapse a master cyl so you just can't get it to work again.The next tool I'd like to get for bleeding is the reverse flow one,these push the fluid from caliper to master cyl,they push the air uphill,the way it wants to go and keep the system pressurised.Sometimes the best thing to do is walk away and come back when you're in a better mood,you'll find it's fixed itself while you were away - really the aireated fluid has released the bubbles which have self bleed back up to the master cyl.

[kerryg]

?

What does it actually do I asks meself? Surely just forces fluid the other way through the system. In this case it would appear once you have the brakes bleed to the point you have then you could just prise the pads away from each other to pressurise the system forcing the fluid back to the MC. With the calliper off you could place it in another position so as to move some trapped bubbles & prise the pads apart again & pump closed. Move to another position & repeat. Do other side.

With my race bike as the MC is at a crazy angle it helps to either lean the bike over against a wall so the MC is flat (helps move any bubbles that may be trapped there & easier to add fluid).

In the bad old pre GSXR days; Suzis used to have anti-dive mechanisms that created extra lever play, they were always fun. If your system was adjusted previously with not enough lever play then it will feel sloppy now. Have you got the original lines on it? They will be well past their best by date now & be as baggy as MC Hammer’s pantaloons.

Hi F5Dave. Yeessssssss buuuuttttt...some of us are lazy bastards and don't want to fgo to any more trouble than they have. I want something that I can use without having to remove the callipers etc if I can. But I hear what you're saying.

It does have anti-dive thingamabobs on it but I don't know if that is an issue or not. I hear they're worse than useless anyway so I'll probably remove them at some stage (when I service the forks...which will be sometime after I have finished bleeding the$%&*&*ing brakes). It's got brand new braided lines that run straight from the master cylinder to the callipers.

[kerryg]

I don't like vacuum bleeders,they can suck air into the system,that's the stuff you are trying to get out!They can collapse a master cyl so you just can't get it to work again.The next tool I'd like to get for bleeding is the reverse flow one,these push the fluid from caliper to master cyl,they push the air uphill,the way it wants to go and keep the system pressurised.Sometimes the best thing to do is walk away and come back when you're in a better mood,you'll find it's fixed itself while you were away - really the aireated fluid has released the bubbles which have self bleed back up to the master cyl.

Yeah I sort of imagined something like this: a big hypodermic filled with brake fluid, with a rubber tube instead of a needle, the tube attached to the nipple and is the fluid is pushed up the lines from calliper to master cylinder...would that work, dya reckon?

[F5 Dave]

Oh yeah didn’t mention that. I have one (for a horse I think) & it was ok I guess, but the oil swells the seal in the syringe & it pops off. Need the type with the o-ring. Never seen one that big (said the actress to the bishop).

Also it was just as likely to slip off & squirt around the side of the bleed nipple.

Yeah I use the leave it over night method as Motu implies. Didn’t think taking the callipers off was that big a deal. The old suzis had a separate external line for the antidive. This compressed a piston & it was this movement that took an extra amount of fluid displacement. Despite the idea behind increasing the compression damping was bollocks & is more likely to make the front wheel lock under braknig.

[kerryg]

Yeah I use the leave it over night method as Motu implies. Didn’t think taking the callipers off was that big a deal. The old suzis had a separate external line for the antidive. This compressed a piston & it was this movement that took an extra amount of fluid displacement. Despite the idea behind increasing the compression damping was bollocks & is more likely to make the front wheel lock under braknig.

Taking the callipers off is simple, true. It's the holding-calliper-in-1-hand-while-trying-not-to-get-fluid-on-the-pads-and-rotors-while-trying-to- wedge-pads-apart-while-wielding -spanner-on-nipple-while-operating-brake-lever.....that I find unappealing.

There is a line to the anti-dive. I'm going to check it out tonight. I'm pretty sure on my bike it's not hydraulic though, but electrical.

[F5 Dave]

No, you misunderwheelstand.

This procedure you are trying to force the fluid & any bubbles in the direction bubbles normal like to travel. Up. Out into the master cylinder. Thus the bleed nipples are closed.

[kerryg]

No, you misunderwheelstand.

This procedure you are trying to force the fluid & any bubbles in the direction bubbles normal like to travel. Up. Out into the master cylinder. Thus the bleed nipples are closed.

Oh...I see...Ok... hey, I knew that

[Drunken Monkey]

Don't know if this will help, but I errr, had problems opening the rear brake pistons on the gixxer, so um, undid the bleed valve and inadvertently bled the mother virtually dry.
Now I did have a one-man-bleed-kit (a small bottle to catch the brake fluid, connected to a hose and a supposed one-way valve). One sore arm and 2 hours later the brakes still weren't firming up. The fluid seemed to move the same direction each pump, despite the one-way valve (probably had a leak somewhere...)
I ended up getting someone to help me with a syringe = he would stick the syringe in the far end and suck while I pumped (man that sounds sick). Anyway, to cut a long story short, that got the brakes up to pressure in about 2 minutes...After that, it was easy to use the one-man-bleed-kit to get rid of the rest of the bubbles.
Sounds like you're having the same problem.

[Jackrat]

This is what I do.
I use a long plastic hose and sit my catch jar about a meter higher than the caliper.I put a little brake fluid into the hose so when I crack the bleed nipple the first air out travels up through this fluid and because it has traveled up hill it's not coming back down.I then leave the nipple open and pump at lest two master cylinder fulls of fluid through the whole system.I don't bother with the open/close thing until I get clean air free fluid coming through.
I then leave it over night and try for proper pressure the next day.
Always works for me.