Clutch hydraulics-to hone, or not to hone?

[John_Mc]

I have the master and slave cylinders out of my car and all disassembled. How do you determine if the insides need honing, or is it just something that should be done each time? It has been 9 years since my last rebuild. Is this an easy thing to do with a local parts store hone like THIS? Thanks for any feedback. I already have the rebuild kits from BPNW.

 

[TR3driver]

I wouldn't call it a matter of course. Basically inspect and feel the bore; if there is some very light damage then honing may be appropriate. If the bore is still smooth, then I wouldn't hone; and if the damage is moderate or severe, then replace it. Honing shortens the life of both the cylinder and the seal, IMO, so it's only appropriate when the cylinder would need to be replaced otherwise (and isn't too badly damaged).

 

[tr8todd]

I have had bad luck with cylinders that have been honed, but have had good luck with the ones cleaned up with some very fine sand paper. Take some 500 grit or better paper, coil it up and slide it into the cylinder. Allow it to expand to the size of the cylinder and twist with either your little finger or something small enough to fit inside. It works better if you wet down the paper with a little brake fluid.

 

[Scott_Hower]

I've had mixed success honing M/C bores, and I have the honing tool with spring loaded stones.
I don't even bother trying with slave cylinders; I just replace them.

As an aside, this tool works great for polishing U joint bores.

 

[HerronScott]

John,

I only have my personal experience with rebuilds and I've always done a very light run-through with the hone with lots of brake fluid present just to try and clean up any glazing or dirt accumulation on the surface. I've never tried or had to use it to "repair" any damage, light or otherwise since my cylinders have been in pretty good shape and in those cases I would probably consider finding a good used one or purchasing a new one.

For me at least, I've never had any problems with the ones that I've rebuilt, British or Japanese.

Scott

 

[John_Mc]

Well, a forged ahead and did what I thought was a light honing job on the slave cylinder. Buckeye Triumphs Webpage indicated that it would be hard to damage the slave cylinder, so I figured I could do it without too much negative consequence. Well...now the rebuilt slave cylinder leaks like crazy when under pressure. I also can't keep the dust cap from popping off. I assume the dust cap is just that- to keep dust out, not hold fluid in, so I wouldn't think that managing to keep that rubber cap on would solve the leakage issue. Any suggestions on why I've created a bigger problem than before, and how to solve it? I'm thinking it's just new slave cylinder time. Frustrating, because prior to rebuilding, it wasn't really leaking noticeably at all.

 

[hondo402000]

I would just get a new one, seems anytime I honed a cylinder out it work for a while but never lasted like a new one, and if you notice at least for new cars. most companies dont even sell kits for brakes anymore you have to buy new master or wheel cylinders

Hondo

 

[TR3driver]

It's possible you just got a bad seal kit. The boot shouldn't pop off like that, unless the leak is so bad that the escaping fluid is blowing it off.

Or it may be that your honing was the straw that broke the camel's back.

The real question is whether you want to risk another $20 to find out; or just buy a new cylinder for $60. Do you feel lucky?

 

[martx-5]

I don't remember, but is it possible to install the seal backwards...

 

[DrEntropy]

Honed many cylinders, the only real enemy is pitting. Rust scale can occur and unless you know what it looks like, chances are you will hone the bore and it will appear to be fine.

The hone should be used the same way as doing a piston cylinder wall: 45° cross-hatch, low speed and lots of brake fluid as "cutting oil".

 

[hondo402000]

yep the elastomer cup does go in a certain direction but not 100 percent but 50/50 chance you can get it in backwards, I think the cup goes toward the back.

hondo.

 

[TR3driver]

As with any cup-like seal, the concave side goes towards the pressure (so the pressure helps force the lip against the sealing surface).

 

[davidk]

Early Six's used a .75 bore rather than a .7 bore. Could you have the wrong rebuild kit?

 

[John_Mc]

Early Six's used a .75 bore rather than a .7 bore. Could you have the wrong rebuild kit?

It's possible. I thought I bought the kit based on my model year. Is there an identifying mark on the cylinder itself?

 

[HerronScott]

The hone should be used the same way as doing a piston cylinder wall: 45° cross-hatch, low speed and lots of brake fluid as "cutting oil".

What the expert said!

John,

Do you have the part number of the rebuild kit you used?

Scott