Yikes - No Brakes - now having trouble diagnosing

[Kidasters]

Well - I went for a drive today to look at a motorcycle, and I figured that it would be good to take the 2002 out for exercise. So - away we go.

The motorcycle was about an hour away. Got halfway there, and while idling at a light, I noticed the brake pedal went to the floor. Pulled over at a wallgreens, and I noticed that the reservoir was 1/4" low. Uh oh.

Kept going to the destination - having to pump the brakes to bulid pressure/stop. Got there, and I could see a small puddle of fluid under the car, and I could smell brake fluid. Couldn't find where the fluid was coming from though (by feeling around with fingers. The puddle was under the booster/master part of the car.

Headed for home via a different/longer way with fewer lights. By the time I got home, the "Brake Failure" red light was lit up on the dash (well - it works).

Some history. Brake master is a Tii master - installed new by me about 2 years ago. Lines from the reservoir to the master are new (blue - bought from Blunt), again, I think 2 years old. Booster is a Tii booster, bought used, painted by me but not rebuilt.

Anyway - got home and into the garage. Pulled the master and the booster. Can't find any problems. Booster is dry inside. When I took the master off f the booster, I heard a "hissss" like there was still some vacuum inside.

I'm stumped. Fluid loss seems like a master failure. External leak though? Reservoir seems fine. Front brakes (re-build a few years ago) fine. Rear brakes? Should be fine. Again - I know something was leaking up front, but now I can't find it.

Thoughts?

Ken

PS - bought the motorcycle. It's a 1966 Bultaco Mercuiro 175. Fun stuff.

Ken

[EngineerTim]

Did you look at your clutch slave cylinder (drawing from same reservoir on these)?

[BillWilliams]

Ken, can't offer any insight but glad you got home ok and you bought the bike

[fxtbass]

Bad master cyl. Leaking out of the back where it bolts to the booster. Pretty common failure.

[BillWilliams]

Dry what you can, then throw some baby powder around that area and pumpem the brakes. The baby powder will show the liquid trail

[andyleonard]

Interesting. So everything has been fine since you did the work and you haven't added any fluid since...and now this? There's no way being 1/4" low on fluid is going to allow the pedal to go to the floor, unless the MC is bypassing inside or the system's open. The MC bypassing inside will not allow the fluid to leak out that fast, if at all...unless it's being sucked towards the booster by a torn diaphragm...and overflowing onto the floor. So there either IS fluid in/on the booster and a torn diaphragm is sucking (a lot of) fluid out the back of the MC and it's running down the front of the booster or you've got cracked brake lines near the MC. Any chance the hard lines at the MC are cross-threaded?

[andyleonard]

(nt)

[Kidasters]

Hey guys - thanks for the replies so far. Let me clear some stuff up....

Clutch slave looks good. Plus - the problem wasn't just losing fluid, it was also brake pedal going to the floor. Plus - when I got home, and the "brake failure" light was on, the fluid reservoir was at the minimum line. So, I lost a lot of fluid.

Bill - thanks and thanks! I'm crazy buying a bike. I rode a very little bit as a kid. I haven't ridden one it around 25 years. I don't even have a MC endorsement. But - it looks like a fun project. I'll post pics in Off Topic when I can find the camera. And the baby powder idea is brilliant, but I've already pulled everything off (crap).

I thought of the seal on the master to the booster, but why would it sound like vacuum releasing when I pulled the master loose from the booster?

Hard lines being crossed is possible. But why fail now?

I'll go look at all of the hard line ends. They were all tight when I pulled the master loose, but that doesn't mean that one isnt crossed.

Sux.

[andyleonard]

As the man said above, having the MC go wonky is a pretty standard theme. Happens a lot. The pedal will fall under steady pressure and you will often see fluid at the joint of the MC and booster. The only thing unusual in your case is the amount of fluid lost in a short time. Usually they go on like this for weeks. Even though it's relatively new, you might pop the MC apart and look at the edges of the rubbers. You're looking for little scratches near the edge or maybe a booger in the valve.

[Kidasters]

Thanks again guys.

I think I'll work on stripping down the master, looking for problems.

I've looked at the hard lines. The two to the left front are new - installed by me when I re-did the tii master. So - they both look good.

The two to the right front look worn. They are original. I can't completely ensure they are in perfect shape. I think I'll order new hard lines to the right front. Good thing I still have the tube bender.

Rats - I didn't need another project....I guess that's old cars though.

Ken

[c.d.iesel]

you said: ........." having to pump the brakes to

bulid pressure/stop. Got there, and I could

see a small puddle of fluid under the car,

and I could smell brake fluid. Couldn't

find where the fluid was coming

from though (by feeling around

with fingers. The puddle was

under the booster/master

part of the car."..........

seems like not much of a problem to see the source

of the leak ?

After all the above back and forth statements,

I'm thinking you have a flared pipe fitting problem?

Doesn't take much for the cone of the fitting

not to be seated squarely? incorrect 'feel' when

you tightened up the pipe fitting?

do keep us updated

p.s.

ditch the 175 Mercuiro and find a 200 Metralla !

here's an excellent source for everything Baltaco

http://www.bultaco.com/

[Kidasters]

Thanks CD. I agree with you. I ordered the following from Blunt today:

2 steel lines from MC to right front wheel

Grommets that go on inner fender for steel lines to pass through

"square" o-ring for the back of master cylinder to the booster.

grommets for the top of the master to the reservoir.

I'll replace the lines.

Yeah - I hear you. I looked for a 250 metralla for awhile, no luck. Trust me though - you'll like what I do to the mercurio. There will be a little TSS on there.....

And I've already been talking to the folks in Craryville. They are the Bultaco Center of Excellence.....

[Kidasters]

OK - So I started removing stuff today, as I got the parts from Steve and got some time. Here's what I found.

Turns out, one of the lines to the right front caliper was rubbing on the steering shaft. My guess is that a few years ago, when I swapped to the Tii booster and master, it pulled the lines up and caused it to start rubbing.

Here's the hole in the brake line:

and, you can see the shiny spot on the steering shaft where it had been rubbing. All of this is hidden by the booster when it is in place:

The new line was kind of a pain to install. I'm sure it would be a piece of cake if the engine was out of the car. But, I didn't want to do that. So - I snaked it in and bent around corners as best I could. It's not my prettiest work, but it will work.

So - now I have to finish getting everything plumbed back to the master, and then bleed. It was time to flush the brake fluid anyway, so I'll switch from ATE blue to ATE Gold.

One final thing - as everything goes back together, I think of all of the tips that I've gotten off the board - specifically the E21 clip on the booster pin!

OK - break's over. Back outside.

Ken

[BillWilliams]

Ken,

Good find! Glad you found it and getting things back together. Yes those lines are a pain to install when the motor is in. Those lines are not that easy when the motor is out at least with my tubing bender skills.

Yes, the e-21 clip saved my religious affiliation. I guess that is why BMW switched to it on the e-21s.

[M2M3M3]

wish i had noticed your thread earlier. i have nearly new set of front brake hard lines....already bent....available. would have been easier to install than starting with new straight lines.