Can't bleed caliper

[superbenk]

When I was trying to bleed my Tie Down surge disc brakes recently I couldn't get one caliper to bleed cleanly. I was using the Mity Vac bleeder & it kept pulling air out of the one caliper. The other side bled fine. I pulled the brake line & hooked up the bleeder directly to it & it bled fine (no bubbles). The caliper is new last year (both replaced) & I only dunk in fresh water. I'm wondering if I have a bad piston seal or something? Anything else it could be? I think I'm getting uneven braking because of it (one tire cupped while the other didn't & now a axle seal shot perhaps due to heat - although hubs don't get hot to the touch).

 

[Grub54891]

Sometimes the air comes through the threads of the bleeder itself. Can't tell ya how to stop it from happening but I've had that happen,I just barely crack the bleeder and go for it.

 

[superbenk]

Would Teflon tape help?

 

[bruceb58]

Would Teflon tape help?

Yes it would.

I use a pressure bleeder up at the master cylinder. I have never had good luck with those Mity Vac styles.

 

[NHGuy]

I did my Tie Downs with a vacuum bleeder. If you break the bleed screw just barely free, maybe it won't suck air. What I am meaning is just open it a few degrees past closed. Or maybe go down the auto parts store and get a new bleeder fitting, it might fit tighter. They will be metric BTW.
Vacuum is a great way to bleed...if you can do it. I guess if you can't vac it down you can actuate the surge mechanism as you would do a foot brake when manual bleeding. Have someone hold pressure while you open the bleeds. It's a PITA, 2 person job. Although if you were desperate you could do the full tube thing where there's a bubble free fluid connection all the way into the catch jar and below the surface of the fluid. That's easy to mess up though.

 

[bruceb58]

With a pressure bleeder, it takes less than 5 minutes per wheel. Buy the Motive bleeder and the adapter that threads right into the master cylinder.

 

[gm280]

With a pressure bleeder, it takes less than 5 minutes per wheel. Buy the Motive bleeder and the adapter that threads right into the master cylinder.

I take it that the Motive pressure system clamps on the master cylinder and forces fluid through the system. And you still have to open each bleeder valve and let the old fluid out with the air. Is that about it?

 

[Scott Danforth]

I recommend speedy bleeders, they have an internal check valve, and they can be purchased in stainless.

 

[smokeonthewater]

Just don't worry about the air bubbles.... Bleed with the vacuum pump till you have the air out of the lines... Then screw the bleeder down with a wrench while still pumping.... Done deal, head for the lake...

 

[bruceb58]

I take it that the Motive pressure system clamps on the master cylinder and forces fluid through the system. And you still have to open each bleeder valve and let the old fluid out with the air. Is that about it?

The adapter fitting I have screws into the master cylinder opening. You also don't have to worry about the master cylinder running out of fluid if you do it right.

 

[Outsider]

Do you have 2-piece bleeders? My Kodiaks did, and bleeding was near impossible until I figured that out ...

 

[superbenk]

Do you have 2-piece bleeders? My Kodiaks did, and bleeding was near impossible until I figured that out ...

What do you mean by 2-piece beeders? They're Tie Down so I don't know if they're the same as the Kodiaks or not. I put Kodiaks on my last boat & never had a problem but I don't remember if they were any different.

 

[Outsider]

Nine years ago, bleeder had two parts, unscrew the distal end and get air/fluid as one would expect. Unscrew the base, you get fluid from around the base and air in. At least that's what the guy laying under the trailer told me, and he wasn't getting paid ... :facepalm:

 

[ezmac]

Try smearing some heavy grease around the threads of the bleeder on the caliper. Heavier the better. That will make a temporary seal and you will be able to pull a vacuume. Do it all the time changing fluid in my motorcycle.

 

[gm280]

Try smearing some heavy grease around the threads of the bleeder on the caliper. Heavier the better. That will make a temporary seal and you will be able to pull a vacuume. Do it all the time changing fluid in my motorcycle.

Sounds like a viable solution to the constant air bubbles... :thumb:

 

[smokeonthewater]

Bad idea.... If ANY amount of that grease contaminates the brake fluid it can swell seals and ruin the caliper.
I admit it's tempting and there's a fair chance nothing bad will happen but IMHO it's just not a good move.