Need extra tips getting air out of ABS unit.

[Hendrixwannnabe1]

Hi there all,

I have just installed a new rotor on front and put new seals in the calipers. After reinstalling components i have been unable to get proper pressure in front brake lever even after bleeding and cycling the abs many times. I have some pressure but need to pull lever right back and its not road safe.
I made the mistake of not plugging the lower banjo bolts somehow and the whole system drained and obviously filled with air.
I just did a standard bleed to prime up the system.
Procedures i have tried since....
*cracking the right bleeder and allowing it to slowly gravity bleed over 30-40mins
*took calipers back off, secured the pistons and suspended them up right from a rope off ceiling, attempted to bleed while they up high.
*compressing lever overnight, both with resevoir open and closed, makes no difference.
*massaged the abs unit and as many pipes and hoses as i could get to with a massage gun, silly i know.
*attempted to reverse bleed, no air comes out of top, only fluid.
*used air compressor pump
* cracked all the banjos i can get to easy

All these techniques simply produce nice clear fluid from bleeders, no air. So its gotta be trapped somewhere.
Im completely out of ideas so willing to attempt anything suggested.
Is it possible to completely remove all braking components and bench prime whole system before reinstalling??
Would attempting to burp and prime the abs module while still under the seat effectivly remove trapped air?? ie. Detach the in and out lines for the front brakes at the module and force fluid into module and hopefully burping out any air?

Rear brakes seem fine and everything else worked fine before i installed new parts.

Thanks, any help much appreciated.

 

[Hendrixwannnabe1]

2010 Super Tenere.

 

[BadNews]

If you’ve followed all the proper brake bleeding procedures and still have no lever, I would suspect something else. Being a 2010, has the front brake master cylinder ever been serviced/replaced?

 

[Doug C]

Hi there all,

I have just installed a new rotor on front and put new seals in the calipers. After reinstalling components i have been unable to get proper pressure in front brake lever even after bleeding and cycling the abs many times. I have some pressure but need to pull lever right back and its not road safe.
I made the mistake of not plugging the lower banjo bolts somehow and the whole system drained and obviously filled with air.
I just did a standard bleed to prime up the system.
Procedures i have tried since....
*cracking the right bleeder and allowing it to slowly gravity bleed over 30-40mins
*took calipers back off, secured the pistons and suspended them up right from a rope off ceiling, attempted to bleed while they up high.
*compressing lever overnight, both with resevoir open and closed, makes no difference.
*massaged the abs unit and as many pipes and hoses as i could get to with a massage gun, silly i know.
*attempted to reverse bleed, no air comes out of top, only fluid.
*used air compressor pump
* cracked all the banjos i can get to easy

All these techniques simply produce nice clear fluid from bleeders, no air. So its gotta be trapped somewhere.
Im completely out of ideas so willing to attempt anything suggested.
Is it possible to completely remove all braking components and bench prime whole system before reinstalling??
Would attempting to burp and prime the abs module while still under the seat effectivly remove trapped air?? ie. Detach the in and out lines for the front brakes at the module and force fluid into module and hopefully burping out any air?

Rear brakes seem fine and everything else worked fine before i installed new parts.

Thanks, any help much appreciated.

In the Brakes section there are three threads right at the top of the list on how to bleed abs unit.

 

[RCinNC]

Have you tried triggering the ABS while you're actually riding, rather than just cycling the pump? I know it's not safe in its current state for actually riding, but I mean just riding down a low friction surface at low speed (like a gravel driveway or wet grass) and braking to the point that the ABS activated. That might force any remaining air out of the pump.

 

[scott123007]

Air might not be your problem. I have struggled with caliper piston seals in the past and have had some that "bind". What happens is the piston seals drag to such a degree that they will either keep the pistons from retracting enough when you release your brake lever, and your brakes will drag, OR in what sounds like your case, they retract the piston so much that when you pull the lever again, most of the stroke is used up just getting the pistons back to where they are pressing against the pads. Although the seals are not directional, you may want to disassemble the calipers again and reverse those seals, and see if it makes any difference at all. If it does, then at least you know you are headed in the right direction. Maybe even install the original seals again.

 

[Hendrixwannnabe1]

If you’ve followed all the proper brake bleeding procedures and still have no lever, I would suspect something else. Being a 2010, has the front brake master cylinder ever been serviced/replaced?

I would suspect not, i got the bike at 50000km and previous owner had only done basic servicing on it, caliper pistons were a mess, hence i embarked on this journey.
Yeah im not 100% sure its air, just seemed the most logical reason.

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[Hendrixwannnabe1]

Air might not be your problem. I have struggled with caliper piston seals in the past and have had some that "bind". What happens is the piston seals drag to such a degree that they will either keep the pistons from retracting enough when you release your brake lever, and your brakes will drag, OR in what sounds like your case, they retract the piston so much that when you pull the lever again, most of the stroke is used up just getting the pistons back to where they are pressing against the pads. Although the seals are not directional, you may want to disassemble the calipers again and reverse those seals, and see if it makes any difference at all. If it does, then at least you know you are headed in the right direction. Maybe even install the original seals again.

Thanks, i think a disassemble is on the card.
Might just take calipers off bike first and see if the piston all move freely still. It took a fair bit of priming initally to get them to grip the pads and then once they did they refused to let go of pads properly until i had built up more pressure.
Will make sure i clamp the damn lines this time.

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[Hendrixwannnabe1]

Have you tried triggering the ABS while you're actually riding, rather than just cycling the pump? I know it's not safe in its current state for actually riding, but I mean just riding down a low friction surface at low speed (like a gravel driveway or wet grass) and braking to the point that the ABS activated. That might force any remaining air out of the pump.

Only on the back brake which triggered abs fine. I will try to trigger the front next time.
Im willing to attempt anything at this point.

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[Hendrixwannnabe1]

Should i have used some rubber greese on the piston seals?? All i used was vrake fluid to lube them up. Wondering if i missed a step?

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[RCinNC]

Brake fluid was the recommendation for lubrication when I rebuilt my rear caliper. In any event, if the brake piston seal was leaking, you should see brake fluid escaping from the caliper.

 

[Hendrixwannnabe1]

So i bought a brake line clamp and clamped it off just above both the calipers and lever movement was instantly about 1/4 what it was before and rock hard after that small movement. So spongy feeling. Take it off and spoongy sensation is there again.
To me this would indicate an issue with calipers or perhaps some air trapped inside calipers that isnt bleeding as it should.

Any thoughts??

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[Gerard]

I had the same issue when overhauling the front calipers, did not plug the lines and lost most of the fluid. It took me forever to bleed them as the manual warns you that that will happen.
End up using a vacuum pump and could not believe the amount of air i got out with it after being absolutely sure there was no air left in the system.

 

[RCinNC]

Are you saying that you clamped both front brake lines at the same time and got a hard lever, or you clamped them one at a time and got a hard lever each time?

 

[Cycledude]

I have Speed Bleeders on my Goldwing and they make bleeding brakes incredibly easy ! someday I’m going to install a set on the Tenere

 

[Hendrixwannnabe1]

Are you saying that you clamped both front brake lines at the same time and got a hard lever, or you clamped them one at a time and got a hard lever each time?

I clamped the line going down from front of engine to left caliper. So both calipers were out of the system. Trying to determine if air was in ABS module or in calipers.

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[Hendrixwannnabe1]

I had the same issue when overhauling the front calipers, did not plug the lines and lost most of the fluid. It took me forever to bleed them as the manual warns you that that will happen.
End up using a vacuum pump and could not believe the amount of air i got out with it after being absolutely sure there was no air left in the system.

Yep its a nightmare. I wish i could get air out with vaccum but all i get is fluid.

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[Hendrixwannnabe1]

When i get a chance after work i might clamp the brake line that crosses over between the 2 calipers and see if the left caliper alone causes spongy feeling in lever. If i can isolate where the issue is coming from in the system will make fixing easier i hope...

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[RCinNC]

When i get a chance after work i might clamp the brake line that crosses over between the 2 calipers and see if the left caliper alone causes spongy feeling in lever. If i can isolate where the issue is coming from in the system will make fixing easier i hope...

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That was what I was getting at; trying to isolate if one caliper or the other was the source of the problem.

 

[Hendrixwannnabe1]

So i clamped the line going between the two calipers and it was soft and spongy. So at the very least i need to investigate the left caliper.

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