ABS Pump Bleeding

[Colin S]

I have just re-built all the calipers on my Mk2 and despite bleeding several times the pedal is not great and feels a bit soft.

I am wondering if air has managed to get into the ABS, although we were careful to only do one at a time.

Does anyone have the procedure for bleeding air out of the ABS pump? Do we need to use a pressure bleeder?

Oh and yes we do have a large swear box ready, and I will be getting my mechanic brother to do it!!

[blackyb]

I help out every now and then at a local garage and for the odd time we have to do a full bleed on an ABS the gaffer uses a fancy pressure bleed system. The secret is tho to not get any air into the block in the first place, so we clamp every hose before we start.

I know that ABS systems can be a nightmare to bleed up.

Patience is the answer.

[Zebbysebby]

Just a word of warning in case you go out to buy a pressure bleeder, I have one like in the picture. It comes with 4 caps and none fitted my Mk1, Clutch or brake Master Cylinder. I suspect the Mk2 is the same. Mine is badged as a Sealey but likely other companies will use the same design. The picture shows it on the CMC but the cap is too big. I did consider buying another Brake master Cylinder cap and adapting it to fit but no guarantee it won’t leak under pressure.

1C209470-F506-436A-B68F-082817BA3DA3.jpeg (503.42 KiB) Viewed 5614 times

[Mazda Mender]

I have just re-built all the calipers on my Mk2 and despite bleeding several times the pedal is not great and feels a bit soft.

I am wondering if air has managed to get into the ABS, although we were careful to only do one at a time.

Does anyone have the procedure for bleeding air out of the ABS pump? Do we need to use a pressure bleeder?

Oh and yes we do have a large swear box ready, and I will be getting my mechanic brother to do it!!

Did the fluid level drop and empty the filler bottle?, how did you block off the brake hose's when removing the calipers?, to much pressure can damage the internal of the hose's?so the fluid has trouble getting past, if it is in the ABS pump, your brother will love you for that job as there is no bleed nipples on the pumps, its a one union at a time job, messy long horrid job, did you bleed off correct??? as the helping foot can get the strokes wrong to opening and closing, and the strokes not long enough?, "IF" the level did not go low, there is something you could try, put her on 4 x axle stands ,remove all the rims, start the engine so the pump is working, "KEEP AN EYE ON THE LEVEL" make sure the helpful foot knows what is required and how, and bleed them off, as a foot note , is the handbrake set correct?
AS Bry as mentioned a fluid pressure sucker is the easy way if it is a one man band and are cheap enough to get off the bay of E, or if you have rebuilt the systems and are fresh and dry.
Try the bleed while running first to see if it helps, rule of thumb is furthest away first working down to the nearest ,so passenger rear, drivers rear, passenger front,drivers front, swap the fronts around with ABS.

Just a word of warning in case you go out to buy a pressure bleeder, I have one like in the picture. It comes with 4 caps and none fitted my Mk1, Clutch or brake Master Cylinder. I suspect the Mk2 is the same. Mine is badged as a Sealey but likely other companies will use the same design. The picture shows it on the CMC but the cap is too big. I did consider buying another Brake master Cylinder cap and adapting it to fit but no guarantee it won’t leak under pressure.

1C209470-F506-436A-B68F-082817BA3DA3.jpeg

We went through this process of testing the "eazy bleed" some years back and tried to adapt a OE lid to seal without any luck so went straight in the bin, so with a fresh master or system build we now just use a liquid sucker on a bleed nipple, bump the pressure up ,open the nipple and pull the fluid through ,kind of the same way they do at the factory only theirs is on a bigger scale , works so much better with less faff and mess, also great when fitting fresh dry clutch lines, fresh masters etc, and the fluid/liquid pump-sucker get used for a lot more jobs,engine oil changes, power steering etc etc.
Otherwise it is an old coffee jar, number 8/9 mm spanner, spare fluid for top up, length of hose, and a helping foot with a " PUMP" "STOP" "PRESS THE PEDAL TO THE FLOOR" "HOLD IT THERE" repeat 3 x or until happy, check level next corner :0).



M-m

[Jetmech]

The way that I did it, when I accidentally allowed the fluid to drain on a new shape Beetle, was to find some loose gravel and deliberately skid the car, setting off the abs. Then bled the brakes again. It worked!