The diagram is available at Craigs place. google (craigs place alfa )and you can find it.
He is kind enough to offer the complete manual with great diagrams.
Usually when the pedal does not return the problem lays in the slave cylinder.

 

Thanks for the info about craig's place, great site. I do have a milano shop manual, but my group 12 section is a joke of only 8 pages, nothing on the master cylinder. Looks like group 12 is supposed to be 40 pages! Unfortunately even the extra pages don't show an exploded view of the clutch master cylinder, only the slave.

It just doesn't seem right that the master would be able to push any fluid back into the reservoir, otherwise it would never compress. The reservoir always has air in it.

 

have you checked your slave cylinder, sometimes if the slave sticks, it will force the fluid back through the master because it can go through the slave. you should go under the car, and have someone press the clutch and check the travel of the slave cylinder.h

 

Larsjm,

I just replaced my clutch master cylinder because the attachment fork where the master cylinder piston rod connects to the clutch pedal was worn pretty bad causing excessive play when engaging the clutch so I had an old one to take apart.

There is no check valve in the supply line that I can tell. It is a pretty simple hydraulic cylinder. The piston has two rubber seals, one at each end. I could see that if the front seal was compromised you might get the problem you describe where a topped off resovoir might act as the resistance for the fluid and allow your clutch to work somewhat with the seal closest to the clutch pedal actually sealing the cylinder. I will try to take some pictures and maybe put together a diagram to show what I am talking about if you think it might help.

I'm thinking it is the master cylinder but a visual check of the slave while actuating the clutch pedal might let you know which one is the culprit.

 

10-1 odds your front seal in the MC is bad...not sure if you can still get just seals..but its a quick and simple rebuild

have you checked that you dont have a leak on the INSIDE!!! of the firewall above your feet..theres a a huge catch lip up there that can catch ALOT of fluid befor it drips down

 

Thanks for all the info, I have checked my master cylinder on the inside, mainly to look at the fun task of getting an allen wrench in there to take off those bolts. There doesn't appear to be any fluid leaking at all. I would agree with torcia and sh0rtlife that I have a bad seal in the MC which is allowing the pressure to flow into the reservoir. My slave cylinder appears to be actuating fine. Diagrams of the MC would really be helpful, or at least some pictures of what it looks like apart.

 

Clutch Master Pictures

Here come some pics.....

First one is a blow-up of all the parts.

Second one is of the piston with the two rubber seals one at the front ...next to the spring and one at the rear.

Third is of the master cylinder from the top and the last one is of the reservoir supply holes. I shined a flashlight into the cylinder so you can see the relative size of the openings. The one towards the front is just a pin-hole compared to the rear hole.

In the blow-up picture I tried to place the piston where it would be "at rest" in relation to the cylinder to show where the front seal would sit under the reservoir supply holes. The front seal very quickly goes past both holes when the clutch is actuated closing off the supply and moving the fluid in the system to actuate the slave cylinder. If the front seal was compromised then you can see that clutch actuation would force fluid into the reservoir (given the rear seal and slave cylinder were still working properly). By closing off the supply then the rear seal would move the fluid in the system and actuate the slave.

Another possibility might be if the front "pin-hole" was blocked somehow. That might cause some problems.....

I'm no hydraulic engineer so I am just guessing...had to get the disclaimer in there

Hope this helps.

 

Yes, this is all very valuable information. Thanks for the great pics, now the system makes sense. Definitely need to order up a master cylinder, which actually brings up another question. I know the clutch slave cylinder is interchangeable between the spider and the milano. What about the master cylinder? From the pictures they look like the exact same part, the only difference being that the one for the spider has it's own reservoir, which would be a nice upgrade to add to the milano.

 

The spider/gtv (115/105) spares I have are 17mm bores on the clutch master cylinder and are ATE parts. The Milano one in the pictures is a Benditalia and measures a 19mm bore. The acuator rod that works on the piston is another problem. On the milano one the fork that attaches to the clutch pedal is pressed on and whereas the spider/gtv one is threaded with an adjustment capability. The actual rod is quite a bit shorter than the spider/gtv one. I got a nice replacement master cylinder from Centerline but I am sure all the usual places would have them. The real fun is getting the old one off!!!!! I have the dash and carpet out of my car at the moment so it was a bit easier for me. Takes a long 6mm hex key to get the cap screws out. I think one that has a kind of a ball on the end would work better so you can angle it a bit.

Good Luck!!!!!

 

I have the same main cylinder on my Bertone 115 from 1974.
Were did you bys repair set for this cylinder?

 

I have the same cylider on my 105/115 from 1974.
We did you get the spare parts from?

 

Repair kit KH9992 ?