Bad slave?

[altiain]

...cylinder, that is.

Here are the symptoms, but I could use a hand with the diagnosis: when I start my car for the first time in the morning, or after it has sat long enough to completely cool down, the clutch pedal will engage almost immediately off the floor. However, once the car has warmed up (especially after 15 minutes or so on the freeway), the clutch will engage almost at the top of its stroke.

It's a noticeable difference - between fully cold and fully warmed up, the engagement point probably moves three inches along the pedal's travel. And it isn't 100% consistent, which is irritating - at one light I'll find myself slipping the clutch too much, and at the next light it will almost bog. Only two repeatable events are engaging abruptly first thing in the morning, and engaging high on the stroke after 10+ minutes of freeway driving.

I've flushed the clutch a couple of times, (even using Billy's postive pressure bleeder) to no avail. I've adjusted the engagement point, to no avail. I'm not losing any fluid, nor do there appear to be any signs of a leak from the master or slave cylinders. The car has 77k miles on it, and it's still got the original master and slave cylinders.

Any suggestions?

Iain

[POS Racing]

I'm thinking slave cylinder. Have you crawled under the car and pulled the boot back to see if there is some moisture behind the boot?

My '92 with almost 150,000 miles still has the original master, but I did have to replace the slave, it acted very similar to what you describe. Mine wasn’t showing signs of loosing fluid either.

Mick

FYI : For a limited time, we will are offering 1 CENT UPS Ground shipping to all ONLINE orders over $20.00. At http://www.mazdamotorsports.com

[sammm]

How much is the rebuild kit from Mazdamotor Mick? My slave needs to be rebuilt as well.

[POS Racing]

How much is the rebuild kit from Mazdamotor Mick? My slave needs to be rebuilt as well.

The entire slave (p/n NA01-41-920B) is about $42.50 From Mazdaspeed, ($56.64 from Trussville) I replaced the entire unit on mine due to the high mileage on my car. I was concerned the slave cylinder boar was worn or scored past the point of a rebuild. Also on mine the pivot point was worn severely where the shaft contacts the shift fork, and the pin was almost totally gone on my car.

This is a picture of a New Slave, not my old one!

[altiain]

Mick, do you know if the p/n for the '99 slave is the same as the one you posted? I always have a hard time using the pdf parts catalog at Mazdaspeed - I can never find what I'm looking for.

While you're at it, how 'bout a p/n for a clutch master cylinder cap? I'd like to make a pressure cap for the clutch as well. Thanks!

Iain

[JRW]

Don't buy a clutch master cylinder cap, I have one that already has a hole in it and a brass hose fitting epoxied in the cap. We should be able to adapt that. I asked for a MC cap and drilled a hole in it before I even opened my hood to see it was the cap for the clutch.

[BigDmiata]

Sounds like the slave cylinder to me too. I'm gonna have to replace mine as well, it's been acting up also. After having mine go out less than a mile from my house once, I've gotten in the habit of carrying a spare one in the trunk.

[POS Racing]

Mick, do you know if the p/n for the '99 slave is the same as the one you posted?

While you're at it, how 'bout a p/n for a clutch master cylinder cap? I'd like to make a pressure cap for the clutch as well. Thanks!

Iain

Slave for a '99 in the PDF files at Mazdaspeed shows the part number to be NA01-41-920! (BTW. Price is the same as for a '92. )

The cap in the PDF files at Mazdaspeed shows the part number to be B093-49-580

The Rebuild Kit, which does not include the Rod, Push but includes the spring and the seal is is p/n H005-49-460

I didn't list any prices, you'll need to log into Mazdaspeed and check prices and availability!

Mick

[altiain]

Thanks Mick - I appreciate it!

Iain

[bigDstars]

There is a slave cylinder epidemic going around now. I replaced mine with a new Brakemaster from O'reiley's (sp?) for about $26. I've been told not to rebuild for some reason. I had 2 quotes from shops for about $150 I think for the job. New one has been in for a couple of weeks and is great so far. As I said in another post, that is very easy to get to, so I had no problem trying the non-Mazda part. One cold morning a couple of weeks ago, I very instantly had no pedal. No warning similar to Ian's. When I called a local Miata shop and described my symptoms, he said "99% probability it's the slave". He was right. (Miata Technologies - they've done some good work for me so far)

[altiain]

Thanks for all of the help and suggestions. I installed a new slave cylinder over the weekend, and that seems to have cured the problem.

Iain

[Miatamaniac92]

Mine went out on Friday!

Chris

[POS Racing]

FYI : Here is a picture of Mazda's rebuild kit p/m FB01-49-460. They also offer just a seal kit, but with this kit you get a new spring & piston as well as the seal, and the boot!

[Miatamaniac92]

I'm just gonna replace the whole thing. It was rebuilt by Rotary Performance by the former owner.
This might fix it a lil longer than 30K miles.

Chris