Alfa Romeo Forums banner

1 - 5 of 5 Posts

·
Premium Member
Joined
·
1,076 Posts
Discussion Starter #1
While many owners are quite fussy about keeping their rides OEM, others like myself, do not see Pebble Beach in their future and are simply looking for reasonably priced equipment to keep the old girl on the road.

A project begun in early December to investigate rear brake noise (left rear brake pads gone, compounded by failed axel seals and congealed diff fluid everywhere, including brake shoes) resulted in an all too common case of massive mission creep, ultimately leading to disassembly of my Ate clutch master cylinder after I noted fluid leakage from the back end of the unit. I found that problem while installing the new brake booster from Vick's that has been in my garage for over a year. Although seal debris was discovered in the MC bore, interior surfaces were clean and smooth and thus began my odyssey in search of a seal kit.

Calls to the usual suspects informed me that numerous bad experiences by vendors having to explain to buyers that the seals they bought were not defective, but likely the result of shortcomings in the cylinder bore, causing rapid failure of replacement seals. By and large our reliable domestic vendors decided to discontinue seal kit offerings, although Ate kits could still be found on eBay, less the front seal I also needed.

During my time down the eBay rabbit hole, I found numerous vendors offering the same Centric MC at an attractive price, but, strangely, only applicable to the last generation Spider (through '94). That seemed quite odd, since as we all know, Spiders shared the same clutch MC throughout the series, with most I believe being Ate and some from another vendor that begins with a B and I'm too lazy to research. Communication with the lowest price vendor (ever notice on eBay how a commodity item will post to eBay with numerous vendors within pennies?) revealed "our catalog shows application only to the vehicle in our listing".

Undeterred, I took iPad2 in hand and finally made contact with Cory in Tech at Centric (877 272 5301) who confirmed their own search function did not display a Spider MC (Milano only) but after further research discovered that indeed (and as suspected) the MC in question does fit most of the Spider line as well as other Alfa models. Cory is a credit to Centric and told me how the company has come to dominate the brake industry and how the founder started the business as an Alfa enthusiast.

For anyone wanting to update their knowledge of braking systems, I recommend a visit to the Centric site, where videos delve into many aspects of brakes systems, including the difference between "abrasive" pad/rotor combinations and "adhesion" systems. At the risk of broadcasting my ignorance (too late?) I always thought black dust on BMW wheels was primarily pad debris. Not so. Also, really cool video of brakes being tested to destruction on their dyno rig.

Where was I?

While, like most BB members, I make every effort to support our faithful BB vendors, I must admit when prices creep into 3 figures (OK, low three figures) the experience of growing up with my dearly departed, Depression-era parents kicks in and I become a bottom feeder...

New MC arrives next week and I'm optimistic it may resolve the occasional "bump" in pedal travel I've been experiencing upon clutch disengagement. Pivot arm has been R&Red as well as slave cylinder. Hope it's not T/O. Maybe junk in the line?

Meanwhile, its back to the always challenging task of brake bleeding. Gonna try a reverse technique this time, pushing fluid up from the calipers. BTW, the booster from Vick's has an adjustable rod to remove some of that pesky free pedal play. Nice!

All the best.
 

·
Premium Member
Joined
·
1,076 Posts
Discussion Starter #2
Clutch Master Cylinder R&R

Installed the new clutch MC last night and as so often happens with tasks that are performed like clockwork, every 20 years, and are not fully thought through before picking up a tool, I took waaaay longer than needed.

I believe Albert Einstein said words to the effect "Whenever I have a project, I spend 90% of my time thinking and planning and 10% doing the work."

If I had followed Al's advice, I would have realized my job would have been easier had I awaited arrival of the MC and attached it to the booster assembly before reinstalling the booster. Still had to loosen the MC anyway, since alignment of the hydraulic line turned into a pia and I needed some wiggle room to get the threads started . Oh well, next time.

Also, the actuator rod on the new MC had been manufacturer adjusted to the correct length so I just tightened the locking nut.

After I got the MC in place, I put about 1" of fluid in the reservoir and opened the actuator bleed screw (which I rotated to the bottom of the actuator to facilitate particulate draining) and used a rubber adapter on my Mity Vac equivalent to push fluid down and out of the system. If the clutch MC is configured internally like the brake MC, the only fluid path when the piston is in the relaxed position is via a small compensating port, which (if I am correct) restricted free flow and provided a degree of resistance to my pumping efforts.

Satisfied I had flushed the hydraulics, I turned my attention to finding Mity Vac adapters for the next step, which would be reverse bleeding of the system from the bottom up. Turned out to be another lengthy, and due to trial and error, sloppy process. Finally got all the connections tight and used the Mity Vac device to pressurize a small, sealed container of fluid that was attached to the bleed screw. I used thin, clear tubing from the fish section of the Petco so I could watch for air and after light pressurization, noted bubbles in the gradually filling reservoir. I stopped the process when the bubbles disappeared, and rotated the bleed screw to the top of the actuator cylinder, although, once the system is bled, not sure that makes any difference. Following a struggle with a frozen OEM actuator years ago, my new one rotates easily.

In years gone by, and following months of disuse, I occasionally found my clutch MC reservoir to be dry, with no signs of fluid anywhere (???). Topping off and pumping a few times restored operation, but from what I have read of the experience of others, sounds like I was fortunate to restore clutch function so easily.

This time, with some degree of anxiety, I got back in my car, pushed the clutch pedal, and although there seems to be a bit more free travel than I recall, the pedal immediately firmed up and I believe function has been restored. I said "believe" since I still need to bleed my overhauled brakes before starting the car, so I'll know for sure soon if all is well.

Also, want to review my shop manual to confirm I'm getting the correct amount of piston travel at the actuator.

Later...
 

·
Premium Member
Joined
·
21,450 Posts
You'd think hydraulics, and their bleeding, would be a straightforward repeatable science. But each car and process seems to have its own quirks. I've had cars bleed cleanly on the first push, others take forever to become right. And Alfa clutch bleeding is almost always an exercise in extensive pumping. The last one I did though, was good in a minute or so. I never know what to expect.

Andrew
 

·
Registered
Joined
·
5,383 Posts
I just finished bleeding the entire clutch system using only gravity on the spider. I filled the reservoir, removed the slave, held in my hand with bleed nipple topmost, and attached a 24 inch piece of tubing to it. Opened the nipple and sucked on the tube until I got fluid out, then let about 50 ml drip into a pan. Closed the nipple installed the slave and done. Maybe I got lucky? I do note that I seem to be limited in slave travel to about .35 inches roughly, a bit below spec. But it releases fine and feels fine so far .... but haven't driven the car ...... yet!
 

·
Premium Member
Joined
·
15,603 Posts
That's how I was able to bleed the clutch hydraulics in the LS in downtown SF several years ago. Of course in that case I just let the fluid dribble out onto the motel parking lot from the slave. We left immediately after that, lol. Clutch worked fine the rest of the drive back to Seattle.
 
1 - 5 of 5 Posts
Top