I'm replacing the leaky brake master cylinder on my FC with a remanufactured unit. The brake fluid pressure switch is stuck in the old BMC. I need to swap it over to the new one. It's the part with the electrical wire sticking out the bottom:
It's 19mm. No matter how hard I try to take the switch out with a wrench or Vise Grips, it won't budge. CRC Screwloose and Freeze Off aren't working either. Any other way I can get this switch out, intact?
Owie. I have never had to remove one of those because I have never seen one. It looks like it's in a perfect spot for moisture from the brake fluid to collect meaning it could very well be rusted into place.
Can you get a new switch?
There's a used one for sale now on evilBay for $19. I'd rather not pay for it, but I might as well. I can't find that switch anywhere else separate and I don't want to risk proper organ function trying to remove the old one for free.
BTW, that switch is for the S4 GXL-exclusive auto-adjusting suspension. The AAS shocks are pretty worn out and I plan on getting Konis at some point, but I still need something to plug that hole in the BMC. Should've went with the non-AAS BMC, but it's too late now.
It shouldn't be that hard to make a plug for the hole out of a bolt and a copper or aluminum washer. I think that's the way I'd go since you won't be using the AAS.
I thought that just as I posted my last message, but I was worried about leaking. Some thread sealer should do the trick. It's off to the hardware store tomorrow. Thanks, Jensenman!
Scratch that. Looks like I will have to buy the switch. I went to two Home Depots and a local hardware store today, and none of them had bolts that would fit. It seems like Mazda used a very fine thread for the switch.
Hit the local junk yard, you might find a bolt that will fit.
There's another GXL at my local pick-a-part, but I don't remember if the BMC was still intact. Hopefully it is and that switch isn't frozen in the cylinder...
Some tips to possibly make removal easier:
Heat and cool the items. Heat the Master Cyinder up with a torch, cool the switch down. The differences in expansion/contraction should help break things loose. You may need to rinse and repeat the process.
Turn the switch the opposite direction. Should help break any gunk in the threads loose (plus it should tell you whether it will ever move)
Obviously, make sure the item is firmly clamped in a vise and feel free to get medieval on it. Use a breaker bar or cheater pipe, jump up and down on the tools, etc. You're not going to reuse the switch, just the threaded portion to plug the hole.
Finally, if you can measure the threads in the MC, and let us know, I'm sure one or more of us could come up with an appropriate plug for your master cylinder.
Do you need the master cylinder as a core? If not, I'd consider cutting it up and chiseling it off the switch.
Are you even sure this switch still works?
In reply to fiat22turbo:
I have tried turning it the other direction and tried using a cheater pipe. No dice. I'll drop by the junkyard tomorrow and check out that GXL; there's a few other odds and ends I have to look for anyways. If there's nothing there or the switch is stuck like mine, I'll ask one of my pals if I could borrow a torch of some sort. I'll also look into some sort of thread-measuring device.
In reply to foxtrapper:
Yes, I need the old master cylinder as a core. I don't care if the switch works or not since AAS is useless and I will be getting Konis anyways; I just need something to plug up the hole.
Found one at the junkyard. Came out easy as pie. Thanks everyone, for your advice.
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