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View Full Version : Ugh, fabricating an intake port/coupling for a Previa clutch master cylinder



mountainhick
10-05-2013, 12:34 PM
A frustrating day yesterday, and the project extended into this morning.

After a couple days waiting for the parts, I rebuilt my clutch master cylinder yesterday. easy peasy.

Then went to install and noticed the fluid intake tube had broken off. I was completely perplexed. Nothing felt like it broke when I removed the hose, it was not inside the hose, and nowhere to be found.

So, no way to hook up the fluid.

How it should look, note the tube:

http://images.oreillyauto.com/parts/img/large/ba/ba0728855-1.jpg

Mine:

http://www.mountainserver.net/previa/clutchcyl-1.jpg



I looked up the part and called Toyota... part discontinued, not available, but can replace entire master cylinder.

UGH!! I don't want to wait another several days, and I don't want the added expense.

Thought about it for a while and figured with some metal I could turn something on my metal lathe to fit the hole and O-ring seal, but then how to add an elbow?

I went to the hardware store (1/2 hr drive each way, like everything where we live), they had the fuse, so I got a couple for backup, and found parts that could work. If I turned down a 1/2" npt-1/4" npt pipe reducer fitting, added an elbow and flange, I could replicate something like the broken plastic part.

I put in the fuse, and it immediately blew. opened the switch/electrical box on the lathe and it is way beyond my ability to troubleshoot.

So another hour of thought and I came up with a makeshift platform to attach a cross slide vise as tool holder, screwed a pneumatic connector into the 1/4" npt fitting, chucked that into a drill chuck, chucked that into my wood lathe chuck and produced a workable part. It was sketchy and I do not recommend anyone do this. There was way too much play in the chucking and movement in the vise/mounting mechanism. Pretty scary really. But it got the job done.

http://www.mountainserver.net/previa/clutchcyl-2.jpg


http://www.mountainserver.net/previa/clutchcyl-3.jpg


So that's as far as I got yesterday. This morning I found a scrap of brass sheet and cut and drilled a flange:

http://www.mountainserver.net/previa/clutchcyl-4.jpg

That is soldered to the NPT flange and the elbow is soldered in to avoid any leaks:

http://www.mountainserver.net/previa/clutchcyl-5.jpg



It works, but what a silly amount of work and energy over this niggly little part.

http://www.mountainserver.net/previa/clutchcyl-6.jpg

timsrv
10-05-2013, 12:52 PM
Lol. Been there done that. Not with this specific part, but I've done this with several other things. I used to be an aircraft toolmaker and had a huge modern machine shop at my disposal. Now I have a garage and a couple pieces of old and/or otherwise inadequate equipment. Still, with a little care and ingenuity it's pretty amazing what you can accomplish. But then there's the time issue. Pure stubbornness for me at times. If I was on the clock some of my manufactured $2 parts would be more like $200.......but there is a degree of satisfaction. Yours looks 10 times better than that plastic junk anyhow :wnk:. Tim