I just put speedbleeders on my 91 K100LT front wheel caliper and ABS unit.  Everything went fine as far as bleeding goes.  I did notice that the OEM bleeder screw on the ABS unit is different than what I call a standard bleeder screw. There is an o-ring to the right of the threads and between the threads and the o-ring is what appears to be a relief cut for fluid flow.  Please take a look at the image below.  Does anyone know if the speedbleeder is an ok substitute for this and that my ABS will still function as intended?

Had I designed it I would have put the reliefe below the thread but providing the O-ring seals in the body of the caliper/ABS modulator then I don't see a problem.

I don't think the relief between the threads and the o ring is for fluid flow. I think it is there for ease of producing the threaded section without creating a stress concentration point. The o ring is there to make bleeding easier - less tendency to leak fluid whilst bleeding or to suck air back in past the threads. Some have used thread tape whilst bleeding to achieve the same effect.

Can't comment on what effect the speed bleeder would have on the brake system as I'm not familiar with these, but as long as they seal the bleed hole in normal operation they cannot influence braking performance (IMO)

I've never seen a bleeder screw like this before.  But your explanation does make some sense.  I wanted to look down into the bleed screw threaded hole to see if there were any paths for fluid other then the bleed hole at the bottom but the brake fluid was coming out so I just put the speedbleeder in it.

Please tell me more about the speedbleeder.

My problem has been that when I use the master cylinder as a bleed pump I end up sucking air past the old hard seals (I've had it open and cleaned everything up but don't want to spend the money on overhaul kit until the thing actually leaks fluid).

Speedbleeders are bleed screws that have a built in check valve.  All you do is loosen the bleed screw and then pump the lever while making sure you don't run the reservoir empty.  No need to open and close the bleed screw each time.  They are very handy on cars where you can't be at both ends at the same time.

http://www.speedbleeder.com/

Ancient eyes were seeing the hole where the red arrow is but after enhansing the pic its at the blue arrow so I totally agree with Rawdon.

Get one of these and you'll never have to fuss with inefficient bleeding of the callipers or ABS in any situation. I recently bled the ABS II on my RS in a full ten minutes, pump, circuits, callipers, hoses, the lot.


$39 at Harbor Freight in the US. Prolly easily a hunnerd in OZ.

Two Wheels Better wrote:Get one of these and you'll never have to fuss with inefficient bleeding of the callipers or ABS in any situation. I recently bled the ABS II on my RS in a full ten minutes, pump, circuits, callipers, hoses, the lot.


$39 at Harbor Freight in the US. Prolly easily a hunnerd in OZ.

Something similar in OZ for less than $34 http://www.ebay.com.au/itm/Hand-Held-Brake-Bleeder-Tester-Set-Bleed-Kit-Vacuum-Pump-Car-Motorbike-Bleeding-/141309788342?hash=item20e6b840b6

I have one at home. I bought it in OZ for about $40 five or six years ago. It broke after the third use, bad diaphragm and a weak trigger - it always bent under pressure. It came in a red plastic box similar to that one.

I also own a cheap vacuum bleeder, but it isn't that successful to be honest. Being rather unsatisfied with it, I bought a couple of Stahlbus brake vent valves, otherwise known as speedbleeders. The design differs from the cheaper speedbleeders on the market, and I believe that they are worth the extra cost.

They are extremely easy to use and very effective. They are not the cheapest things on the market, but they make bleeding and fluid changes child's play. You will save their cost on the first use compared with a visit to a mechanic. I bought mine from Motorworks.