Leaking Clutch Master Cylinder After Stage 3 Competition Clutch Install

Smoked the stock clutch in my 2013 supercharged Tacoma and replaced it with a Stage 3 Competition Clutch from URD.



Not even 1,000 miles later the clutch master started leaking. Truck has a total of 10,000 miles on it. The master is made of plastic. Spoke to Gadget at URD and he said he never heard of this problem. The clutch spring pressure is stiffer than stock and that's what blew the seals. Probably gonna leak again cause I'm replacing it with the same part.



The master gets fed from the reservoir in the engine bay which is separate from the master assembly.



I pinched the feed line with a clamp so the brake fluid from the reservoir wouldn't spill all over inside the cab. Line the floor of the cab with rags or newspaper to soak up spilled brake fluid.



-Remove the pressure line with a 10mm (flare wrench would be best to avoid rounding the fitting).

-Remove the clutch start switch so you can reach the 2 12mm bolts that hold the master on the pedal assembly.

-Remove the 2 12mm bolts then remove the hose clamp and feed line from the master assembly.

-Measure the pushrod and make sure the new one is adjusted to the same length as the one you removed.

-Grease the end of the pushrod to avoid clutch pedal squeaks.

-Bolt everything back up in reverse order but leave the pressure line off.

-Bleed procedure:
1) Take the clamp off the feed line.
2) Fill the reservoir with brake fluid.
3) Put a rag on the end of the pressure outlet of the master.
4) Press the clutch pedal to the floor. Fluid with squirt out.
5) Put your finger over the pressure outlet and pull the pedal back out (it will stick to the floor after you press it down).
6) Repeat 4 and 5 until you get a steady flow of fluid out of the pressure outlet. You have bench bled the master. Always monitor fluid level in reservoir.
7) Reconnect the pressure line and tighten.
8) Connect a vinyl hose to the bleed port on the slave.
9) Have an assistant pump the clutch pedal 3 times then hold it to the floor.
10) Crack open the bleed fitting (10mm) then close it.
11) Repeat 9 and 10 until no air comes out of the hose and you have a solid pedal. Always monitor fluid level in reservoir.

Done!

 

If anyone is aware of an upgraded aftermarket clutch master cylinder for 05+ Tacomas let me know. Plastic crap sucks!

 

The aftermarket needs to design a better master cylinder assembly. The cylinder bore and piston are plastic. Double seals would be nice too.

 

Have all of the ones from older year model's been replaced with a newer style? If so, I would try to snag one from a used Tacoma, or if there is a different part number at Toyota for the older year models.

I have a decent amount of spring pressure with my twin disk and haven't had a single issue with that. Mine is an '06.

 

I've heard that there are aftermarket metal master cylinders available. I need to do some searching. Weird that Gadget at URD never heard of this problem before.

 

Found one!

http://www.partsgeek.com/gbproducts...+Google+Base&gclid=CK_qtdWDir4CFY17fgod05AAZw

 

Necro bump. Having a similar issue to this right now with my 2011 at 68k miles and stock clutch.

I've ordered Aisin part# CMT-199 which looks to be made of metal. Will update with observations I find during install.

 

Make doubly sure you are using the correct fluid. I had a Triumph Spitfire that required Castrol LMA brake fluid for the clutch and brakes. The clutch master was low and I topped it off with Dot 3 fluid. It leaked by the next day. I got a new cylinder and LMA fluid, no more problem. You may want to get fluid from the dealer if not absolutely sure.

 

I think the cap on the res just says DOT 3 (although 4 should also be fine) - are you aware of any particular requirement beyond that?

Mine is not actually leaking visibly at this point, but binding up in the bore when it gets below 40F overnight and the plastic clevis portion of the push-rod has also broken so it makes the pedal action pretty funky and noisy.

 

No, i'm not aware however, the Triumph rubber seals swelled and leaked with DOT 3. LMA was required. Plastics may do a similar thing if incompatible. I would see what the dealer provides to be sure and use that. Just like antifreeze, use the wrong formulation and you have a whole lot of trouble. It's cheaper to use the right stuff in the long run.