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Clutch master cylinder overhaul #5

Regarding the clutch master cylinder which I repaired the hole at piston with solder, one of my friend advised me that the solder might not be hard enough.  Therefore, I tried the repair again in another way.
Disassembled the clutch master cylinder again.

Now I can do it very quickly because I disassembled brake master and clutch master cylinders many times J
Heated and removed the solder at the piston hole. I used the soldering iron instead of the burner because I heard giving too much heat on piston should be avoided.
In this time, according to the advice from my friend, the repair method is to screw in the thread with strong adhesive into the hole, then grind the thread head to make the piston surface flat.  In order to do it I bought bolts and a grinding stone at the hardware store.

Cutting the bolt to adjust the length to fit the hole depth. 

Engrave the minus groove at the cut bolt head to make screwing in possible with minus screw driver.

It took time, but the result was not bad.
Paste …
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Clutch master cylinder overhaul #4

The overhaul of the clutch master cylinder, which I succeeded in the removal and repair of the piston with solder (probably), has been still continuing. 
The master cylinder was disassembled and all parts were cleaned.  The condition of each part was not bad.

In the last week the cylinder and rod were painted.

Assembly started.  I checked the condition of the rubber parts originally used comparing with ones of the repair kit.  And I decided to use the original ones because the rubber was not deteriorated yet and the quality looked better than the repair kit’s one.

Always the assembly is fast although I always struggled with the disassembly.


The overhauled master cylinder could be operated smoothly.  And I believe the appearance also became cleaner.

(My original blog was written on 26th Jul. 2009)

Clutch master cylinder overhaul #3

I was still struggling with the sticking piston of the clutch master cylinder. I thought I should give up and look for the new part for the replacement.  And to for my curiosity, I started to destroy and disassemble the clutch master cylinder piston by drilling.
When I was drilling the piston halfway, I didn’t have any specific idea, however, I thought to tap the piston to make the thread.  I started to turn the tap handle, and I felt the feeling that the piston was moved.  So, I tried to pull it, and then suddenly the piston was removed from the cylinder.

Finally I could extract the rusty piston!
I observed the extracted piston.  It looked there was no risk of the leakage of the fluid because the hole I made in the piston was not penetrated.  Thinking the function that this part only holding the rod connected with the clutch pedal, it could be reused if the hole would be filled by the hard material.

However, before repairing the holed piston, I started to restore the cylinder because repa…

Clutch master cylinder overhaul #2: tough match

I disassembled the removed clutch master cylinder.

And I found that the piston was heavily rusted.

I tried to hit it with a hummer,

Pushed the piston using the vise clamp like this.  However, the piston was heavily sticking by rust and it could not to be moved today.
The brake master cylinder was replaced in the past, however, the clutch master cylinder was not.  Therefore, the condition of the clutch master cylinder might be worse.
Tentatively, I would spray the rust-penetration lubricant from both sides of the piston and try again in a few days.

If it doesn’t work, I would give up the overhaul and order the new part.

(My original blog was written on 2nd July 2009)

Next task is to overhaul the rusty clutch master cylinder

The overhaul of the brake master cylinder was finished and I’ve started the overhaul of the clutch master cylinder located at next to the renewed brake master cylinder.
I started from the removal of the pipe lines.

In one of the pipe lines, however, the flare nut and pipe were stuck together.  The pipe would be twisted in case the flare nut was turned.  I tried several methods, such as blowing the lubricant or knocking the nut, to avoid collapsing the pipe.  However, it seemed there is no way.  So, I gave up rescuing this pipe line.

I separated the other end of the pipe (clutch slave cylinder side) and removed the clutch master cylinder with the pipe line.

I had to create the new pipe line by copper pipe. I’ve started to look for the pipe flaring tool on the internet auction.

I did one another small improvement. The O rings at the acceleration pump jet plugs of WEBER carbs were deteriorated by gasoline so that I replaced them with the gasoline-resistant O rings made by fluorine rubber.  Howe…

Brake master cylinder overhaul #4

I disassembled the brake master cylinder again I repaired on the other day because the behavior of the piston seemed to be not smooth enough. 

When I removed the piston at the last time, I checked the condition of the rubber and it looked good.  Therefore, I reassembled it without replacing the rubber. However, again I disassembled the brake master cylinder’s piston and checked its condition carefully in order to reassure myself.

I disassembled and cleaned the piston and the spring.

The condition of the original rubber was not bad, but I replaced it once with the rubber part of the repair kit.

Again, however, I felt that the quality of the rubber parts of the repair kit (left one) seemed to be poor….

I also assembled the piston into the cylinder as a trial, however, the tight contacting feeling was not enough.
As my conclusion, I judged the condition of the original rubber parts were good enough and decided to reuse them. So, I reassembled with the original rubber parts again.
When I was reass…

Brake master cylinder overhaul #3

I cleaned the inside of the master cylinder again using the honing machine.

I removed the rust from the spacers, nuts and washers which were used for fixing the brake master cylinder on the body,

and painted the brake master cylinder, the linkage rod and other small parts. I did the “home made baking finish painting” with the electric heater.

Apply the brake fluid on the piston and insert it to the cylinder.

Assemble the piston push rod, which to be connected to the linkage rod, in the order of (1) ~ (6).

#1 rod to be inserted to #2 washer, and it to be fixed in the groove inside the cylinder with the circlip .

And set the #4 plate on it, insert the #5 spring and fix the spring with #6 nut.