I-ABS bleeding question

[PAS]

2003 R1150RT

Is there a trick to keep air bubbles from forming in the hose when bleeding the front and rear control circuits and integral circuits? (all the smaller bleed points)

Would a dab of grease at the base of each one help?

 

Thanks

[dirtrider]

2003 R1150RT

Is there a trick to keep air bubbles from forming in the hose when bleeding the front and rear control circuits and integral circuits? (all the smaller bleed points)

Would a dab of grease at the base of each one help?

 

Thanks

 

Morning PAS

 

Yes, sort of anyhow.

 

Just place your bleed fluid container & bleed hose exit ABOVE the bleed nipple threads.

 

If the bleed hose exit & fluid container is below the bleed nipple threads then a siphon occurs that sucks those small air bubbles into the bleed hose at the bleed screw threads.

 

If the hose exit & container is above the bleeder screw thread level then the remaining fluid in the bleed hose tends to back flow just enough to prevent those little air bubbles in the bleed hose.

 

But, other than a distraction, those little evenly spaced tiny air bubbles seen in the bleed hose mean nothing as it is just a little external air being sucked into the bleed hose at the bleed nipple threads (those threads are external to the caliper or ABS controller).

 

[PAS]

Thank you D.R.!! Your a valuable resource to all of us and your input is deeply appreciated!

[joeb]

Howdy. I have same bike and had same issue. I just didn't open bleed screw as much and bubbles stopped forming. And as DR stated, the leak from the bleed nipple doesn't compromise the process.

[Lowndes]

I found that a few wraps of PVC thread tape work really well to keep the threads from leaking air and fluid when bleeding. Just be sure to not wrap onto the conical seating end of the bleed fitting.

 

It does take a few more wraps to seal than a pipe thread which is tapered and somewhat self-sealing. These bleed fittings are machine screw threads and straight. Experiment with the number of wraps, not enough won't seal, too many won't allow the fitting to start in the hole. I think it took 6 or 8 wraps on mine. It also helps to do a quick taper at the seat end.

 

If you don't have any thread tape handy, a plastic shopping bag cut into strips works, too.

 

If you have the short bleed fittings, the PVC tape can usually be split easily to make it narrow enough to fit the thread.

 

Be sure to wrap in the same direction as you would to turn a nut onto the thread.

 

Thread tape works really well on shotgun choke tubes, too.

[dirtrider]

I found that a few wraps of PVC thread tape work really well to keep the threads from leaking air and fluid when bleeding. Just be sure to not wrap onto the conical seating end of the bleed fitting.

 

It does take a few more wraps to seal than a pipe thread which is tapered and somewhat self-sealing. These bleed fittings are machine screw threads and straight. Experiment with the number of wraps, not enough won't seal, too many won't allow the fitting to start in the hole. I think it took 6 or 8 wraps on mine. It also helps to do a quick taper at the seat end.

 

If you don't have any thread tape handy, a plastic shopping bag cut into strips works, too.

 

If you have the short bleed fittings, the PVC tape can usually be split easily to make it narrow enough to fit the thread.

 

Be sure to wrap in the same direction as you would to turn a nut onto the thread.

 

Thread tape works really well on shotgun choke tubes, too.

 

Morning Lowndes

 

Using PVC or PTFE thread tape on any hydraulic fitting is risky. In fact the company that I work for has banned any thread tapes in the vicinity due to possible usage on brake systems & fuel injection systems.

 

All it takes is for a small thread or piece of that thread tape to get cut off by the threads then work it's way into a hydraulic control valves (like the ABS system) & cause a valve failure) or into a (fuel injection system) & plug a fuel injector.

 

This can be very risky on the ABS control side bleeders as they are right on top of the ABS controller & the bleed screws are opened & closed many times during a bleed procedure therefore increasing the possibility of working a piece of cut thread tape into the ABS unit.

 

I know you seem to be using it with success but this is just a warning to others to be very careful in using any type of thread tape around critical hydraulic systems as sharp threads can cut it then debris can enter the hydraulic system.