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- Thread starter Welder Dave
- Start date
1693TA
Senior Member
I had that on an old Mack truck from the 30's. I opened the bore of the wheel cylinder, then sleeved it down to a standard 3/4" bore with honed 304 tube and no problems afterward.
Most anything is doable with enough gumption applied.
Welder Dave
Senior Member
1693TA
Senior Member
Good to read and glad he took care of you. Looks like it will work to me.
Started my DCC-353 machine today and was thinking of you but didn't weld anything; just exercised the engine and electrical output with a space heater.
Welder Dave
Senior Member
It's great there's someone who tries hard to support the older Champions but man do you pay for it. I just couldn't see spending $925 (tax incl.) for a used unit even though it was rebuilt. If the seal blows in this one it looks like it shouldn't be difficult or expensive to find a replacement. I suspect the bad one would likely need to be bored out and need more than just a cup seal. I can take it apart and if it's salvageable keep it for a spare if it's not too much to fix. If I wasn't in a hurry I might have waited to see what the brake shop said regarding fixing it. I certainly didn't want to wait over a month for them to just look at it.
Welder Dave
Senior Member
I didn't hear back from the president of the company after sending a pic. of the repaired slave so I called him today. I think he was hoping I wouldn't worry about a partial refund. He was worried the welding may have damaged the slave but other than heat marks the bore is perfect. I shouldn't have had to call him but I got the refund he promised. I'd give them 4.5 stars out of 5 only because he should have called me with his concerns and not waited for me to call back.
Welder Dave
Senior Member
I went out to install the slave. I had to change the fitting for the brake hose because it was too small but the old fitting was in pretty good shape so I reused it. Had a bit of an oh $hit moment when after thinking I had it bled started the grader and it didn't work. I put a board on the pedal and went to the other side to see if the slave was doing anything. It was pushed out about an inch. This was encouraging and there wasn't brake fluid blown out all over the place. I pumped the pedal till it got hard and stuck the board on it. Then I loosened the bleeder screw again. Fluid came out but no air bubbles I could notice. I started the grader and success, I had a clutch. I shut it off and topped up the fluid. I used almost all of a new 500ml bottle of brake fluid but the slave is 1 1/2" bore and about 3-3 1/2" stroke. Quite a bit more capacity than most. I had a larger bottle of brake fluid left over from when I put the new master cylinder on earlier in the summer but reading that opened brake fluid will absorb water figured I should use new fluid from a sealed container. I'm a happy camper and hopefully no other issues with getting the clutch to work properly. It sure wasn't cheap but I did save over $250 on all the components compared to going to the dealer that specializes in them. If there is still a tiny air bubble will it eventually work out of the system?
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1693TA
Senior Member
If the brake fluid was kept in a sealed container I would have no problems using it until about three years of opened age. I purchase brake fluid by the gallon as less expensive that way but I use it over about a year.
Entrained air will usually escape from the system over time and usage. You can expedite this by parking the machine with the bleeder screw end higher than the other, allow a several hour dwell time in this position than bleed again. A power bleeder, or glass jar, clear hose, and your board to block the actuator pedal down work well also.
Welder Dave
Senior Member
I read where someone said not to use brake fluid after 3 month's. I think I have 98-99% of the air bled. It doesn't use a conventional bleeder but just a thumb screw vent. I had a fairly hard pedal and stuck the board on it tight, then opened the bleed screw and had a nice stream of brake fluid come out. After that I couldn't even push the pedal with my foot after taking the board out. I took the cap off and topped up the master so I think it should be good.
Welder Dave
Senior Member
I went out today and there was brake fluid on the bottom eye bolt of the slave but it could be from bleeding. I used the grader to rip the MX track so used the clutch several times and it was working good. I think if it was leaking the clutch would have stopped working because the fluid would have been pumped out of the master cylinder. I also noticed the piston didn't retract all the way. This might be normal because when it's fully retracted the rubber seal is part way over the ports on the slave cylinder. It was noticeable when I first opened the box with the slave. Being all the way retracted may be another reason a little brake fluid may have leaked. I pushed it all the way in but after using the grader noticed the piston was back to being out about 1/4"- 5/16". This puts the rubber cup seal fully below the ports. When I go out again I'll check if the bottom eye bolt is wet and how the clutch works. I think it's probably OK.
1693TA
Senior Member
They have said for years that brake fluid draws moisture and this is true but I believe it's misrepresented to the consumer. My beliefs are more along the line of the temperature extremes this fluid has to bear in use; not so much in a sealed container in a shop.
Think about it, all master cylinders are vented to atmosphere to allow for expansion as the fluid heats. Most automotive master cylinders are under the hood in close proximity to an engine that gets quite warm in operation which through simple conduction, the master cylinder, and contained fluid absorbs some of this heat. Now add the heat of brake operation and the fluid absorbs some of this through the wheel cylinders and metal brake lines. Now think about the engine being shut down and the vehicle not being operated. You have a cool down cycle now going and as a fluid or gas cools, it can draw moisture from the humidity in the surrounding air. Over a period of time, you have contaminated brake fluid but the system has never had anything but brake fluid put into it.
I'm sure brake fluids of days gone by were more susceptible to this than later fluids but it's still relevant as you see some nasty crap come out of brake systems when they are opened up for maintenance or repairs.
Think about it, all master cylinders are vented to atmosphere to allow for expansion as the fluid heats. Most automotive master cylinders are under the hood in close proximity to an engine that gets quite warm in operation which through simple conduction, the master cylinder, and contained fluid absorbs some of this heat. Now add the heat of brake operation and the fluid absorbs some of this through the wheel cylinders and metal brake lines. Now think about the engine being shut down and the vehicle not being operated. You have a cool down cycle now going and as a fluid or gas cools, it can draw moisture from the humidity in the surrounding air. Over a period of time, you have contaminated brake fluid but the system has never had anything but brake fluid put into it.
I'm sure brake fluids of days gone by were more susceptible to this than later fluids but it's still relevant as you see some nasty crap come out of brake systems when they are opened up for maintenance or repairs.
Welder Dave
Senior Member
I read where some brake fluid (maybe most) is packaged with nitrogen to elimate moisture pick up. The fluid I could have used was left in an unheated shop so went from hot summer temps. to below freezing so may have been more susceptible to moisture pick up. They have test strips that measure copper levels but I'm not sure if they have them for checking water content. There are testers for anti-freeze that maybe something similar could be used for brake fluid but brake fluid isn't very expensive. I figured for $7.99 I'd just use a new bottle since everything else is new. Just hope it isn't leaking. They said they'd warranty the slave cylinder if it was modified but I really doubt it since he was concerned about welding the proper fittings on. It's a standard cup seal like used in master cylinders and the bore looks like it was honed so I can't really see how it could leak. After the weird things I've had happen I'm a little paranoid after spending over $700 for the slave cylinder and having to modify it. I figured it was worth the risk and saved about $200.
Welder Dave
Senior Member
Thinking about it more the plunger out a little (and easy to push back in) could be the freeplay for the clutch that they specify should be min. 1/8". I wasn't sure where you measure the freeplay. I can't see it but feeling the snap ring it's closer to a 1/4" out from the end of the slave. Next time I go out hopefully no more fluid on the bottom eye bolt. I can't see how the new seal could leak unless it was damaged. It wasn't hard to put it back in and the bore was honed pretty smooth so I don't think the seal got damaged.