Front brake master question

[SoCal250]

Has anyone here worked on a front brake master similar to this one from my TZR250 3XV?

I got it all cleaned up and rebuilt and then realized I had not removed the elbow tube for the reservoir. I want to make sure there's no debris in there and that the tiny bleed hole is clear. Air blows through it OK so the larger fill hole is clear.

I removed the rubber boot and the snap ring but the plastic elbow fitting won't budge, even with some pulling and twisting back and forth. I was afraid of breaking it. Is it just a friction fit into the body? I know there's an O-ring under it. TIA

[85RZwade]

I've done'em, and it's a friction fit with an O-ring. If it's not moving, it'd be nice to have a replacement elbow on hand...just in case. Maybe a little heat on the master cylinder body would help.

[SoCal250]

No spare elbow on hand. So I CAN'T break it, I have a very important event in less than 10 days I'm trying to get this ready for. I have a little PB Blaster soaking in the well around the fitting. We'll see if that helps.
This is why you shouldn't let your brakes go for 20 years!

[m in sc]

throw some wd down the side of it and hit the body of the master with a heat gun, lightly. it will come out with steady smooth pressure.

[SoCal250]

After soaking for several hours with PB Blaster and then a few more with WD I hit it with a hair drier (don't have a heat gun), and then very carefully with a micro butane torch. Still won't budge.
I'll go out tomorrow and get a proper heat gun. It's something I've been needing for a while anyway. Then we'll give it another go. I may just have to leave it as-is and hope it works OK.

[Striker1423]

Having never worked on this, take it with a grain of salt. Plastics don't like weird torque. Straight pull back without grasping at the 90 degree bend. Grabbing the elbow at the bend is how it'll break.

I bet that O-ring inside has 20 years of brake fluid that swelled it.

Could you ultrasonic cleaner it and see if that helps?

[kpke]

Yikes. I hope it comes apart in one piece.

May I ask, what is the event you are taking the bike to?

[SoCal250]

Having never worked on this, take it with a grain of salt. Plastics don't like weird torque. Straight pull back without grasping at the 90 degree bend. Grabbing the elbow at the bend is how it'll break.

I bet that O-ring inside has 20 years of brake fluid that swelled it.

Could you ultrasonic cleaner it and see if that helps?

Oh, I'm well aware of how fragile that plastic elbow is! It's more than 30 years old and pretty flimsy. I've been very carefully applying even pulling torque down at the base, and gently twisting while make sure not to tweak the 90.

Yep, the O-ring is likely shot, just like the outer caliper piston seals were. I have 2 new O-rings on the way. 

It's already been through 2 cycles in the ultrasonic (20min & 10min) at 45-50C. I may run it through one more time while I'm working on stuff today since the master is disassembled again.

[m in sc]

i mean, if its not leaking and wont move, just blast brake clean thru it and it should be fine. me? id run it at this point as is.


.02

[SoCal250]

i mean, if its not leaking and wont move, just blast brake clean thru it and it should be fine. me? id run it at this point as is.

That's what I've done so far. At first I was just going to assemble it and run it as-is.
I just wanted to be sure that both holes are clear especially the tiny bleed hole, and that there's no corrosion debris in there. I've run it through the ultrasonic several times, and blasted brake clean and air through it. I would hate to be on a long ride or miles from home and have the brakes start dragging because crap is in there.

[SoCal250]

Yikes. I hope it comes apart in one piece.
May I ask, what is the event you are taking the bike to?

I learned that the master unit is the same as the 97-07 YZF600 and that it's still available new from Yamaha, however I don't think I could get it in time and I may as well see if mine can be cleaned up. It's only the elbow holding me back currently. The bore is perfect.
I'm planning to do this year's Rainey's Ride the Races at Laguna. Should be fun with all those legends! The TZR is my first choice for the ride but I have back-up bikes just in case it's not ready in time.

I need to have this bike done with plenty of time for shakedown runs and to put some mileage on it before the event. I don't want to be "the guy" who breaks down on a 100-mile group ride.

[Striker1423]

Man, I know how that works. This GT750 is the new bane of my existence. It's nice to know though, that the RD has been replaced as the official pain in my ass.

[1976RD400C]

Since the hole is so tiny in there, how about a shot of compressed air right in the elbow?

[SoCal250]

Since the hole is so tiny in there, how about a shot of compressed air right in the elbow?

That's been done multiple times. Air passes through fine. There are 2 holes in there and I'm concerned about the smaller of the two, and if there's any crusty stuff hanging out inside.

[m in sc]

if you bench bleed it and it suctions back its fine. i wouldn't sweat it russ, especially if it was ok prior. .02