Bleeding ABS Brakes

[Dark Horse]

Have any of you guys fitted a front brake piston / seals ( the one in the fluid reservoir , NOT in a caliper) on an ABS equipped model , and then gone on to successfully bleed the brake afterwards ?
I'm aware that the proper procedure necessitates the use of Digital Technician 2 , but I don't fancy shelling out another £100 after only having the job done last year by my local Harley dealership ,(they also replaced the fluid) , and I've read that using Digital Technician 2 is only to fully ensure 100% that no air remains.
I've heard or read that the job CAN be done without the Tech equipment but never been able to find out whether there's a technique !
Since the work involves only the highest point of the braking system , surely any air would rise into the fluid reservoir , in which I would hope to retain enough fluid to prevent air entering the system.
The piston / seals were replaced last year due to the brake light staying on after the lever was released. This totally cured the problem at the time.
Surely the problem shouldn't reoccur after such a short period of time !
My bike is a 2013 Fat Bob (ABS)
Regards

 

[tourbox]

I have heard or read somewhere that after bleeding your brakes you can do the following; Take it down the road and hit your brakes rather aggressively, then speed up & repeat, several times.
It is my understanding that this makes the ABS pulse to clear the air from the ABS hydraulic unit. Does this work, I don't know and would probably not try it for myself. I would prefer to have it done correctly.
tourbox

 

[Dark Horse]

I have heard or read somewhere that after bleeding your brakes you can do the following; Take it down the road and hit your brakes rather aggressively, then speed up & repeat, several times.
It is my understanding that this makes the ABS pulse to clear the air from the ABS hydraulic unit. Does this work, I don't know and would probably not try it for myself. I would prefer to have it done correctly.
tourbox

Yes , this does sound vaguely familiar !
Your advice on the safety aspect of this makes total sense !
Many thanks for your reply !

 

[Breeze3at]

I seem to remember (that doesn't inspire much faith) reading the digital tech insures that the ABS manifold is activated, thus purging old fluid from it. I know I have read of successful bleeding one system (F. or R.) without it.

 

[Dark Horse]

I know for a fact that the manifold does indeed need to be activated when replacing / renewing fluid and there's no way of avoiding it , but I'm hoping that by me only ''disturbing" the front brake master cylinder , I can avoid anything to do with the manifold.

 

[joel]

When we replace a master cylinder at our auto service centre we bleed right at the connecting lines.
Many times we don't need to bleed the system at the wheels do to not opening anything down stream prior to the service.
But many vehicles require the ABS activated bleeding procedure or you end up with a soft pedal.
If your going to try bleeding only the master cylinder it may be best to have a helper doing the lever, a bucket hanging below the connection, the bike draped with wet blankets to protect it from splatter. Hand full of rag to try to absorb the fluid coming out.
Don't squeeze the lever fast, do it slow to help minimize the spay.
Than look over the bike to be sure no brake fluid is on any painted area, brake fluid eats it.

 

[Blue Wide Glide]

Keep in mind that the front brake lines go to the ABS unit and then to the reservoir.

 

[Dark Horse]

That's an excellent point !
Something I hadn't considered !

 

[Dark Horse]

When we replace a master cylinder at our auto service centre we bleed right at the connecting lines.
Many times we don't need to bleed the system at the wheels do to not opening anything down stream prior to the service.
But many vehicles require the ABS activated bleeding procedure or you end up with a soft pedal.
If your going to try bleeding only the master cylinder it may be best to have a helper doing the lever, a bucket hanging below the connection, the bike draped with wet blankets to protect it from splatter. Hand full of rag to try to absorb the fluid coming out.
Don't squeeze the lever fast, do it slow to help minimize the spay.
Than look over the bike to be sure no brake fluid is on any painted area, brake fluid eats it.

Thanks ! Some handy tips here !