101 Sprint, hydraulic clutch help wanted - Alfa Romeo Bulletin Board & Forums
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post #1 of 19 (permalink) Old 07-31-2017, 04:47 AM Thread Starter
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101 Sprint, hydraulic clutch help wanted

Dear all,

last year I've bought a disassembled 101 Sprint from 1962. Completely stripped with all parts in boxes. Re-build is going quite nicely but last week I ran into a problem with which you can hopefully help me: the 101 has a 105 1600 engine with a hydraulic clutch. Previous owner has changed the chassis to provide room for the master clutch cylinder. So far so good. He also welded a bracket to the frame for the slave cylinder. This slave is supposed to connect to the pedal box (see attached picture). I've installed all the stuff, mounted all oil pipes. Now it turns out that the provided slave cylinder (s. image) doesn't work - the stroke of the cylinder is too short and doesn't build up pressure. I am unable to contact the previous owner and hopefully you can help:
Do I need a different slave cylinder? Or a different mount for the cylinder?

Any suggestions / images welcome!

Regards,
Jan
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post #2 of 19 (permalink) Old 07-31-2017, 06:49 AM
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A Girling clutch MC must come from a British model, so if you can figure out what it is, find the matching slave? That doesn't mean the stroke would be right for the Alfa clutch, but with lever length changes you ought to be able to work that out. 105/115 hydraulic clutches didn't use this setup, though maybe 102 2000/2600 did?
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post #3 of 19 (permalink) Old 07-31-2017, 08:24 AM
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Hi Jan

Only the last of the 105's used the hydraulic clutch, what engine is in your Sprint - size and engine number so we can see what you have.

With luck you will be able to fit a mechanical clutch bell housing and go back to what should be there.

Where are you in the world ?

Ciao
Greig
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post #4 of 19 (permalink) Old 07-31-2017, 06:48 PM
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I agree with Greig that buying a transmission bell housing that uses a mechanical clutch is much easier to install than a hydraulic setup. The cars that I owned that used a hydraulic clutch were 105 2000 cars and they used a different flywheel and bell housing. The clutch and brake peddles were from the top and not from the bottom.
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post #5 of 19 (permalink) Old 07-31-2017, 08:09 PM
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Quote:
Originally Posted by janh2 View Post
the 101 has a 105 1600 engine with a hydraulic clutch.
Uhh, that doesn't compute. Are you sure your 101 doesn't have a 1750 or 2L engine & bellhousing installed? Perhaps there were 1600's with hydraulic clutches in Europe, but such a thing was never imported here to the US.

That's why AlfistiSA's question about where you are is pertinent.

Quote:
He also welded a bracket to the frame for the slave cylinder. This slave is supposed to connect to the pedal box
You may be mixing up the term "slave cylinder" and "clutch master cylinder". The cylinder that is actuated by the pedal is called the clutch master. The cylinder on the bellhousing that drives the throw-out fork is the slave.

It sounds like the previous owner made modifications to accept a Girling clutch master, and that cylinder doesn't displace enough fluid to release the clutch. But over the internet, I can't diagnose whether the Girling clutch master is just too small, or whether the cylinder you have is defective.

What does the hydraulic thing on the bellhousing (e.g., the slave cylinder) look like? Does it mount into a hoop on the bellhousing, retained by two, large circlips? Does it look like:


Jay Mackro
San Juan Capistrano, CA

'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 07-31-2017 at 08:16 PM.
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post #6 of 19 (permalink) Old 08-01-2017, 06:13 AM Thread Starter
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Guys - thank you for all the reactions!

@Alfajay - you are correct: I mixed up the cylinder names again.
Further clarification - the Sprint has a 1600 engine from a 105 Giulia model and is completely original, with hydraulic clutch. The slave cylinder is exactly as pictured by AlfaJay. I will try to get hold of a master cylinder from a 105 model (with standing pedals). I don't know how to fit it yet, but certainly that should work?

Regards,
Jan
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post #7 of 19 (permalink) Old 08-01-2017, 07:25 AM
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Quote:
Originally Posted by janh2 View Post
I will try to get hold of a master cylinder from a 105 model (with standing pedals). I don't know how to fit it yet, but certainly that should work?
Jan:

I can't guarantee that the clutch master cylinder from a 105 model (with standing pedals) will work in your 101. Two points:

- I have a clutch master cylinder from a 105 model (with standing pedals) in my '66 Sprint GT, combined with the type of slave cylinder pictured in post #5 and it works fine. So yes, that master-slave combination can work well.

- However, I don't know what distance the 101 pedal assembly moves your clutch master's input rod. The 105 pedal box was designed to actuate a hydraulic clutch master and may have a longer lever (than the 101 box) to give more travel.

There are a lot of considerations whenever you re-engineer something. For this problem, the product of the shaft movement and the master cylinder area must match what Alfa used on hydraulic clutch cars. If your 101 pedal assembly only pushes the rod for 3/4 the distance that the 105 pedal did, then you need a master with 1-1/3 the area to get the same fluid displacement.

Since you already have a bracket for a Girling clutch master welded into your car, if the Girling cylinder is too small, a simpler solution might just be to try finding a larger diameter Girling cylinder that will bolt into the same bracket.

Or, perhaps the Girling cylinder that you have is sized properly, but its seals have worn out.

Note that the master cylinder from a 105 model (with standing pedals) mounts very differently than the Girling cylinder that you pictured (see first photo below). If you decide to use an Alfa clutch master, one from a GTV-6 will be more similar (see second photo below).




Jay Mackro
San Juan Capistrano, CA

'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 08-01-2017 at 07:43 AM.
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post #8 of 19 (permalink) Old 08-01-2017, 07:33 AM Thread Starter
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Thank Jay - I see you point! Worth testing... I'll let you know the outcome!

Jan
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post #9 of 19 (permalink) Old 08-01-2017, 08:58 AM
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Andrew is correct: 102 and 106 cars used the Girling No. 112 7/8" clutch slave cylinder shown in post #1, driven by a No. 103 5/8" clutch master cylinder (the No. refers to an illustration showing the design and the cylinder components). Both types of cylinders are available on eBay at reasonable prices (I paid about USD 70 for a new master cylinder a couple of years ago).

The area of a 5/8" circle is half (50%) that of a 7/8" circle, hence the pedal movement on the master cylinder is twice that of the push rod movement in the slave cylinder, and the forces to push the clutch pedal are half of what they would be in a 1:1 relationship. Clutch cylinder slave push rod travel length for disengaging the clutch was about 1/2" with a master cylinder travel length of about 1" (see excerpts from 2600 and 105 shop manuals below). Further to Jay's points about differences between 105 and 101 travel length, I would suggest one should take both travel length and push force into consideration.

I hope this information helps to find an acceptable solution by first figuring out pedal activation distance, then calculating the pedal activation to slave activation ratio, and from there selecting the cylinder diameter. Girling made the same design available with various piston diameters, typically in 1/8" increments around or below 1".

BTW, Girling seems to have manufactured 3 standard rod lengths for the No. 112 slave cylinder (about 7" was used on the 2600). So, if the notion mentioned in post #1 that "the stroke of the cylinder is too short" applies to the slave cylinder, a rod with a different length may be required.


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-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]

Last edited by tubut; 08-01-2017 at 09:16 AM.
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post #10 of 19 (permalink) Old 08-01-2017, 09:29 AM
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For reference, here are the relevant pages from the Giulietta shop manual (from CarDisc CD):

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-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #11 of 19 (permalink) Old 08-01-2017, 11:47 PM
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To be honest, it would be far simpler just to go back to the mechanical clutch, yes it's a bit of work to pull the gearbox and source the right bits, but it puts things back the way that they should be and at least everything works as it should and retains the value of the vehicle.

The easiest is to source a complete new gearbox from an early cable clutch 105 - assuming your current gearbox is good, then just swap the internals into the early casing and go with the mechanical bell housing and the linkages shown in Ruedi's workshop manual diagram - page 93.

I have an early 105 box in my '61 Sprint, got the car like this and it's no problem at all, the gearbox cradle needs to be shimmed to suit the larger rear mount, but that's hardly an issue.

Where are you in the world ?? I have a spare U shaped yoke, but I'm at the bottom end of the African continent and shipping is costly

Ciao
Greig
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post #12 of 19 (permalink) Old 08-02-2017, 04:17 AM
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Greig is absolutely correct...cut your losses and convert back to a mechanical set-up.

Stuart
'57 Spider Veloce, '57 Lightweight, '60 SZ, '76 2000 Spider. '60 Sprint
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post #13 of 19 (permalink) Old 08-02-2017, 06:19 AM Thread Starter
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Thank you all guys! Great input!

I will give it a thought for a couple of days (and start my search for parts)! I will keep you posted on the developments.

Regards,
Jan
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post #14 of 19 (permalink) Old 08-02-2017, 09:08 AM
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Jan,
It is quite safe to display you location in your profile, this will avoid Greig having to ask twice where you are in the world
All you have to do is go to your user CP and then "edit your profile" and fill in as much detail as you wish to.
Regards, Nick

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post #15 of 19 (permalink) Old 08-02-2017, 10:34 PM Thread Starter
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I am in the Netherlands (and will update my profile in a minute!

Regards,
Jan
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