Technical Help required from our Italian members

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Technical Help required from our Italian members

the hobbler

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I require some help please, probably from our Italian members of the Forum.
A colleague and I decided that as we were both planning to fit front brake discs to our 500s we would look at ways to upgrade the brake master-cylinder. We found a master-cylinder called a "Mini-servo brake master-cylinder". Externally the same dimensions, but producing 30% more braking effort. As it was a straight swap with the standard master-cylinder, this seemed a sensible route to take. We ordered, and received, the items along with the appropriate (or so we were told) brake light switch. Slight problem--the master cylinders don't work (they won't pressurise the brake system) and the brake-light switches don't fit! The supplier (a well known Italian company who don't normally deal outside Italy--I have Italian contacts) doesn't feel prepared to answer our correspondence, and the other companies who supply the same item (often under slightly different names, but in the pictures they all have exactly the same casting marks), aren't prepared to disclose either they supplier or the manufacturer--who we are assured is Italian.
The help that I require is this:---can any of our Italian Forum members find the name of either (a) the supplier and/or, (b) the manufacturer? Any help would be very much appreciated because at the moment both my colleague and I have expensive pieces of useless cast-iron sitting on our work benches--we are NOT amused!
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Tom - i have also bought one of these master cylinders.
When you state that they will not pressurise - can you embellish this statement?
I have fitted mine and have long pedal travel as explained earlier this week.
I do not recall any issues regarding the brake light switch - but haven't livened up the electricals - thats this weekend.
Maybe I'm considering excessive pedal travel - and you see not pressurised?
 
Tom, have a look here, model 0070 as cast on the side.
http://www.golinelliloris.com/prodotto/pompe-freno-mini-servo-800-miniservo-0070/
There are lots of discussions on Italian forums about this item - higher pressure achieved with a smaller piston diameter (F=PxA) for the same foot force. Also seems it may be sensitive to having the correct/ longer pedal rod adjustment - if it is smaller diameter it would require longer travel than standard to shift the same volume of fluid for the calipers/ cylinders to move.
The pressure switch fit may be a taperered thread issue? (assuming it is the correct thread etc to start with), a couple of wraps of ptfe tape might answer that. (Or blank it and fit an R/126 pedal mounted brake switch)
 
Thank you 'Andrew', 'Paolo66' and |'Cambio' for your responses, much appreciated. I will look into all your suggestions and up-date you with the outcome. Andrew, 2 questions; (1) which brake-light switch did you fit and, (2) are you going to initially try a longer operating rod? It might be that you have to get a standard rod and lengthen it, but to what length I honestly don't know. Maybe the 126 rod is longer than the 500 rod anyway. I did find a site where they listed 2 lengths of operating rod, I will try and find it again and advise you.
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This may explain why I have a "long" pedal? It's pressurised - but uncomfortably long in it's travel.
I'm due to make a new pedal "rod" next week.
I'll keep you informed
 
I will be very interested in the outcome of using a longer operating rod--that may indeed turn out to be the answer. What brake-light switch did you use on the end of the master-cylinder Andrew--that is another of our problems.
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I plan to make my own rod from 10mm steel bar. I was going to make it the length Tom quoted @ 75mm - but now I'm going to experiment.
I used my existing brake light switch with ptfe tape applied. Cannot recall an issue.
 
Thank you for that snippet of information Andrew---can I be very cheeky and ask:---who did you get your 'mini-servo master-cylinder' from? I ask that because we cannot, as yet, find a brake-light switch that will fit into the master-cylinder!
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Tom, Have you identified the thread required on the brake light switch in order to fit your new master cylinder?

www.autoelectricsupplies.co.uk list 4 types

1/8th x 27 NPTF with either screw or Lucar terminals
3/8th x 24 UNF with Lucar terminals
M10 x 1 mm with Lucar terminals.

Hth,

Al.
 
Tom, have a look here, model 0070 as cast on the side.
http://www.golinelliloris.com/prodotto/pompe-freno-mini-servo-800-miniservo-0070/
There are lots of discussions on Italian forums about this item - higher pressure achieved with a smaller piston diameter (F=PxA) for the same foot force. Also seems it may be sensitive to having the correct/ longer pedal rod adjustment - if it is smaller diameter it would require longer travel than standard to shift the same volume of fluid for the calipers/ cylinders to move.
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I think "cambio" has 'hit the nail on the head'.

If I was converting a 500 to front discs, I think I'd look to see what master cylinder is fitted elsewhere in the Fiat range. e.g. 850 Sport had front discs whereas the 850 Saloon did not. Then I'd try to find out what difference, if any, there is between the master cylinders for both models. Then see if this master cyl. had the same fitting arrangement as the 500 and might be used. Early Fiat 124's had discs all-round and a single circuit master cylinder not unlike the one shown in 'cambio's link above. I don't recall pedal travel being too excessive.

If anything, I'd opt for a larger bore master cylinder to displace more fluid per stroke needed to operate front discs (bigger pistons) and accept I'd have to push harder on the pedal. I'd rather have a short travel, heavy pedal than a long travel, light to apply pedal.

Al.
 
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Thank you for doing that Andrew---your Italian is most probably a LOT better than mine. Just for interest, who is the manufacturer?---is it 'Golinelliloris?
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Yes - I've asked if a different pedal box is needed.
I've also bought a used 126 pedal box to see if the piston rod is different.
My guess is that a longer rod is the answer.
I'm not sure what length a 500 rod is but a 126 rod is 72mm.
I will update.
I also bought a standard master cylinder to get me road legal.
Maybe an adjustable length pedal rod would be ideal.
Tom.....Do you believe that's this issue with yours? You mention that you couldn't pressurise yours... ,is it most likely that you cannot push the master cylinder piston in enough?
 
A Bing search shows www.golinelliloris.com. Their website can be converted to English by clicking on the UK flag near the top of the page.

Company appears to be Golinelli S.n.c.

Email:- [email protected] They say they will provide any necessary info......


Al.
 
Can you not measure what length of pushrod is required?

With master cylinder removed, measure stroke of pushrod from brake pedal fully up to fully down. Compare this measurement with stroke of piston in master cylinder. This tells you if you have enough travel of the pushrod in order to fully operate the master cylinder. You'll need full travel of the m. cyl. piston in order to bleed the brakes manually (old school!). This doesn't apply if you pressure or vacuum bleed the brakes. But having the capability to operate the m. cyl. piston through it's full stroke is a good safety feature.

Next measure from centre of pushrod mounting hole on brake pedal to the mounting face for the master cylinder with the pedal fully up. Then measure how much pushrod enters the end of the m.cyl. piston in relation to the m. cyl. mounting face. Add these two measurements together. Deduct 1 or 2 mm for some free play. This is the length of pushrod that you require. If you fit a longer pushrod than this in order to be able to push the m. cyl. piston to the end of it's bore, you may close off the recovery port from the master cylinder to the fluid reservoir and cause the brakes to bind as they heat up.

A simpler way to determine length of pushrod needed would be to leave master cylinder in place, remove pushrod, insert a length of wire or rod into the master cylinder piston bore (where pushrod goes) and mark the wire/rod where it aligns with the centre of the pushrod mounting pin/hole on the brake pedal with the pedal fully up. Again deduct 1 or 2 mm for freeplay.

You could also (space permitting) disconnect the pushrod from the brake pedal, push it full into the master cylinder and compare where it's mounting eye/hole now sits in relation to it's mounting on the brake pedal.

Re:- possible source of pushrods and adjustable pushrods. Check out brake servos as fitted to various older cars. Some have a removeable pushrod with either a fork (clevis) or a large eye fixing. Other side of servo (where master cylinder is mounted) often has an adjustable pushrod. This might be useable or at least give you an idea of how to build in adjustability safely.

If you fabricate a pushrod from 10mm rod, you may need to taper the section which enters the back of the m. cyl. piston, as it's bore is often tapered. Plus hole in dust seal on m. cyl. is usually smaller, c.8mm.

Al.
 
Al - Tom - many thanks for this......
I used a vacuum bleed - this may explain how i got a pedal when others couldn't- Tom did you use the pedal method for bleeding?
As i stated previously- i have bought a 126 pedal box and conventional master cylinder and will update with my findings.
 
Morning Andrew;
We only tried the 'pedal' method of bleeding, but not only did my colleague have great problem in getting a 'pedal', when he did get one that was 'sort of acceptable', he found that constant pressure on the brake pedal slowly degraded the hardness of the pedal and the brake pedal slowly went to the floor. With regard to the brake-light switch, (we bought the switch that NANNI advises on their web-site is the one for the Mini-servo)they wouldn't fit AT ALL. The diameter of the switch thread is slightly greater than the female thread in the end 'nut' on the master-cylinder. I have subsequently discovered that the 'original' master switch possibly uses an 'imperial' thread (1/8--poss UNF )--in an Italian master-cylinder!
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The thread pitch is possibly 'NPTF', rather than UNF---and the switches marketed by 'auto electrical supplies' have 'ITALY' stamped on them!
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I take it that you tried the original 500 switch in the uprated master cylinder?
 
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