Fiero Clutch Actuator Rebuild and Bleeder Tool Invention by Keith Peterson

Our Fieros are getting up in years and miles now, enough time for the seals to start to harden and the systems to gather a little dirt. My '88 Formula reminded me of this with a change in behavior of the clutch. It did not let me down, but it let me know it wanted to be fixed with an interesting failure mode. If I pushed rapidly on the clutch it worked, but a gentle pressure would cause the pedal to sink nearly to the floor. It lasted while I researched this phenomenon.

The data is all over the web, so I will not go through it here. I ended up making a bet that it was the Master Cylinder, and purchased the Master Cylinder rebuild kit, taking care to order the right one. Being an '88, mine is the 'reservoir in the middle' type.

These things really come out easily, and the gunk I found inside told me I had picked the right one. The master came apart easily; it cleaned up well in my homemade parts cleaning basin. The new parts went together as advertised. I found the spring inside the master broken: perhaps that had caused the little click I had been starting to hear.

The parts (see Master Cylinder Parts photo) are the ones removed from the Master Cylinder. This was an easy task, and should not be a problem for anyone as long as the cylinder is in otherwise good shape. All I needed to do now was bleed the system. But the project got tricky when I tried to loosen the bleeder on the Slave Cylinder. It was rusted solid.

I was surprised to learn that a very small web with a cross section a little larger than a 1/8” ID pipe connected the portion of the factory slave bleeder threads that thread into the cylinder. I rather quickly twisted it off. If you try this, hold that chunk of metal with a vise grip and you may have a chance to loosen it.

My favorite parts shop found a new Slave Cylinder at the Ray-Bestos factory in Woodstock, IL and within a couple of days I was back on the project. I chose to ignore the advice of many who said 'only get factory clutch actuator parts' and was pleased to see that this brand at least is a very robust cast-iron part, without the weakness in the factory part that made me need a new one.

Before putting all these new parts to work, I blew the line clear from the back with compressed air. I was feeling pretty smart about putting the front end of the line into a pop can to catch the fluid until the air blast neatly emptied all the captured fluid over the car. If you try this I would suggest a milk bottle.

The new Slave Cylinder fit well, connected fine and bled easily, thanks to the bleeding tool I had built for the brakes. It worked great for the clutch as well.  Some project in the past had prompted me to purchase a hand vacuum pump, an item that had proven it's worth on several occasions when I was tracking down vacuum leaks. It seemed the perfect tool for a bleeding system.

I started with a peanut butter jar, the plastic kind that will not break when you drop it. I picked two 3/8-inch bolts and drilled a small hole down their centers. This is harder than it sounds. It took a couple of bits to get the job done.  Then I ground down the threaded ends of the bolts so I could slip a small hose over the end. I cheated and used my lathe for this, but you could do it with a steady hand and a bench grinder, or even a file and enough patience.

I drilled two holes in the lid of the peanut butter jar, threaded in the bolts from the inside out and put the lid back on. It holds vacuum well even without a gasket on the lid.  The first step of the bleeding process is to remove the bleeder screw and coat the threads with anti-seize (see Bleeder Top photo). This might seem like planning ahead for next time, but actually it filled the threads so they would not leak air while bleeding... a lesson I learned while doing brakes with this tool.

I plumbed up the system, filled the reservoir, pulled a little vacuum on the bottle and loosened the bleeder. Not much, and not for long, because the clutch has a very small reservoir and I did not want to accidentally empty it. Been there, done that, started over.  Refill, repump, and then pull a bit more air. Things got much easier once I started getting a little fluid because at last I could see how much I was pulling between refills.

Eventually I started to get solid fluid with no bubbles. I tried the clutch a few times, and at one point really puzzled myself, as the bleeder no longer would pull fluid. It took me a few minutes to figure out that the clutch pedal had not come completely up, leaving the intake port of the master covered and cutting off any new fluid.

Shortly I was getting solid fluid flow from the bleeder and the pedal feel seemed pretty good. I rolled the car out and did a full suds wash job at midnight to remove the brake fluid before it could eat the paint, and looked forward to my morning commute.

My Fiero got me there and back, but things were still imperfect. My clutch pedal still had that little click in the action, perhaps a bit worse and the engagement point was not where it should be. Back in the shop, this time determined to do it more ‘right’ than quick (in other words, I started the project before 11PM).

The click turned out to be play between the clutch pedal and the actuating rod, which folks seem to call the banjo based on its shape. The extra motion I was putting into my clutch action just made it more obvious. I cut a thin shim from an old bit of thin tube and slipped it between pin and bushing and the click was gone.

But the soft feel was clearly air in the system, so we were back to bleeding. This time I jacked up the left rear corner of the car, thinking that would help the bubbles find the bleeder valve. I reinstalled my vacuum bottle and immediately pulled a few more bubbles from the system (see the clutch article by V8 Archie in this issue as to why there was still air in the system!).

I played it very safe: bleed a little, exercised the clutch a little, and then bled a little again. Finally I had that solid feel back after I stopped getting bubbles; things were back to normal. Total cost was about $50 for the Master Cylinder rebuild kit, $106 for the new slave and a few bucks for fluid. Not a bad project at all.

Keith Peterson Hampshire IL