69 USA Duetto Braking question

roland · #1 (**permalink**) 03-20-2003, 02:02 AM

Hello,
I am restoring my 1969 USA Duetto and am faced with the dual brake booster system found in 1969. I have not yet gotten under the car but I am trying to find a schematic or an explanation for how the system works and what booster drives which brakes etc.... It is a dual circuit braking system with 2 boosters but 1 master cylinder (or 2 ?)..
I very much appreciate any explanation from any 1969 US braking afficionado.
Thanks

Roland
Paris France

**papajam** · #2 (**permalink**) 03-20-2003, 04:09 PM

Hi Roland,
The '69 US version Alfas have a dual circuit brake system that uses two boosters and one floor mounted dual circuit (or tandem) master cylinder. The top m/c in the attached pic is a standard ATE 22mm single circuit floor mounted cylinder. The bottom one is the one you have; an ATE 22mm floor mounted tandem cylinder for a lefthand drive car. The righthand drive tandem masters are different and not interchangable with LHD, but that's a discussion for another day.

The brake fluid reservoir is split into two chambers. Refering to the pic, the fluid from the front chamber goes to port #3 (the portion of the cylinder toward the rear of the car). When the brakes are applied, the fluid comes out port #4 and ends up in the side (just above the vacuum hose fitting) of the fender side booster after going thru the left side of the pressure switch cluster (more on that later). The fluid then exits the rear (the skinny end) of the booster and goes to a "T" fitting that's mounted on the lower right side of the firewall. Then it's on to the front calipers.

The rear chamber of the reservoir feeds the rear brakes thru ports #1 & #2 of the master and the firewall side booster.

The pressure switch cluster has two brake light switches activated by pressure, one in the front circuit and the other in the rear and third a switch for the brake failure warning light. The brake failure switch is a piston in a cylinder that is kept centered by equal pressure on both sides. If there's a pressure loss in one of the brake circuits, the piston moves in it's bore and provides a ground for the brake failure light.

Parts for this extremely rare m/c are available from www.alfastop.co.uk/english/index.html .

Hope this helps.

roland · #3 (**permalink**) 03-21-2003, 11:38 AM

Jim, many thanks.. great explanation... It is all clear to me know.... I had an old picture of the bottom of the car and noticed a second MC under the floor on the other side of the transmission. Is it a clutch MC ?
Also I noticed in back of the car a gizmo along the brake line.. It only has one input and one output so it isn't there to balance pressure between two lines.. What is it for ?
Here is the problem I have: When at a stop light and braking, my foot applied to the brake pedal would slowly go to the floor and I would lose the brakes.. So I would raise my foot and apply pressure again. It would be OK until my foot would again slowly go to the floor.. Is it bad seals in the brake MC ? If it is, Is it a simple dismantle, clean (changes seals they exist seperatly ?) change seals and put back together ?
Many thanks

Roland
Paris France

roland · #4 (**permalink**) 03-21-2003, 11:40 AM

Jim,
here is a second pic with the rear brake line gizmo...

Roland

**papajam** · #5 (**permalink**) 03-21-2003, 05:41 PM

Pretty clean looking underbody there Roland! What's the mileage? And how did a US spider end up in France?

The brake and clutch master cylinders are just as you labeled them in the pic; brake m/c on the inside of the chassis rail and the clutch on the outside.

The gizmo (technical term) is a brake fluid pressure regulator. It's supposed to limit the amount of pressure to the rear brakes to eliminate/reduce rear wheel lockup under hard braking. Don't know if it's too effective though. Used to run time trials with the added weight of the spare in the trunk to prevent unintended acceleration about the yaw axis while braking into a turn. After changing to an aftermarket adjustable regulator, I could run without the spare. It may just have been a bad regulator but the phycological advantage of an adjustable regulator was worth at least a second a lap!

If the brake pedal of any vehicle slowly sinks under foot pressure and there are no hydraulic leaks, then the primary seals in the master are kaput (a 'G' rated technical term). The seal kit available from Alfastop has the 5 piston seals, bellows and the sealing washer for the front brake piston limit bolt. Their full kit, manufactured by ATE, includes the pistons and check valves as well as all the seals. Light rust in the cylinder bore can be honed out but any pitting or scoring will require a re-sleeve.

PS - maybe it's the photo or my glasses are crooked but the track rod looks bent.

roland · #6 (**permalink**) 03-24-2003, 06:01 AM

Jim,
Thanks.. i'll look into dismantling the MC to find out the pb.

To answer your initial question, this Duetto was imported by a friend of mine (women) from San Francisco (car from Hawai) into france but left it in a garage for 3 years with no particular care... My friend eventually sold it to me. A very sad thing happened a few weeks later as I was going to have the car's brakes redone (poor braking after 3 yrs in storage)... We were caught in a 5 car pile up on a french highway... We were the last car in line (no rear damage). I could not compete with the ABS brakes of modern cars and were not prudent enough (lesson to be learned) with distances between cars in heavy traffic.... Well here are 3 pics to describe the damage... Insurance does not cover repairs so I am trying to find good but economical ways to reapir. I have found 2 duetto shells (for the front body parts - new parts is too expensive).... The rest I will by from distibutors of try to find good condition old parts... Everything if pretty available here (for a price !) .. a few parts I am having trouble with is the water pump which seems to be specific to spica injected (therefore US) versions. I'll try to get it form the states. Other than that the project has not yet started as I am still negotiating for the body shell. I have 2 relatively inexpensive body shps interested. One (already done a great job on a friends coda tronca) will take parts from the duetto shell, the other has an original engine bay body assembly which he wishes to use. Body panels he said he can save or make from scratch (incl rebending bumbers etc... severe metal working capability ??).... Any thoughts ?
Thanks

Roland

roland · #7 (**permalink**) 03-24-2003, 06:02 AM

2nd pic

roland · #8 (**permalink**) 03-24-2003, 06:05 AM

3rd pic of very sad incident.

**Sniady** · #9 (**permalink**) 03-24-2003, 12:40 PM

more picture's on your car

My 69 US duetto in Paris

**papajam** · #10 (**permalink**) 03-24-2003, 02:33 PM

OUCH!! Brings a tear to my eye. Even the right front floor looks damaged. You might want to try Richard Banks at www.alfaholics.com in England. He has a bunch of used stuff as well as the Spica version water pump.

**John M** · #11 (**permalink**) 03-24-2003, 05:16 PM

Hey Roland:

Sorry about your luck. I had a similar accident last fall. Your damage looks more significant than mine. Sheet metal wise, looks like you just need the hood, upper and lower nose, and the passenger side fender. From the looks of it there is no way those will be straightened. No doubt you will need that upper radiator support with the hood hinges and under hood valence. A good nose clip will have it all. I am surprised it got to your pass. front wheel. Looks like that center steering rod is bent and your wheels splayed out. Maybe a little frame damage to that pass. wheel assembly to be pulled. Bottom other than that looks pretty good. I think your radiator is pretty common. I see it has the curved neck on the top. I know early Bosch Spiders and Spica Spiders had those as well. www.international-auto.com has new water pumps for spica injected cars. Looks like it was a beautiful car and well taken care of. She will be as good as new when the shop gets done.

Best of Luck,
John M

**ossodiseppia** · #12 (**permalink**) 10-25-2003, 09:42 PM

Hi Roland. What's the status of you 69 Spider? Are you restoring it? If so, hows it going. Got any pics?

roland · #13 (**permalink**) 10-27-2003, 06:58 AM

Ossodisepia,
First of all I saw your pics posted online... Beautifull work !!
I am way behind you and will probably not go as far due to budget, tooling and timing restrictions but my restoration will be a nuts and bolt as your is.
Where am I ? Well, I have dismantled the whole car (engine and trans out 2 weeks ago) except the suspension. my next project is to build an inexpensive dolly so I can remove the suspension. By the way how heavy is the empty body ? Can 1, 2 or + people lift it ?
I have a few pics posted (see link below) but will be redoing and extending the picture selection in the next week to make it more interesting.
I additionnaly have hundreds of pictures of my car at every step of the dismantling. I have lots of disk space and bought a 4M pixel digicamera this year so I shoot anything I dismantle . I assume this will be the best tool to hep me remember how to put things back together when the time comes. If you need anything please just let me know and I will send you pics of it.

Quick question. i am asking myself how to recondition the suspension. Do I change all the bushings ? How do I clean up the parts and what are the steps/products to refinish them with ?

Glad to be of any help. You can contact me directly if you wish at tricot.roland@wanadoo.fr

Roland

**ossodiseppia** · #14 (**permalink**) 10-27-2003, 08:39 AM

Hi Roland,

When I dismantled my car, I took as many pictures as I could. I did not have a digital camera back then. The digital camera is the way to go, because you can check your pics on the spot. In some cases, I didn't take enough pictures or missed some things altogether. The digital camera should solve this problem for you.

I'm not sure how much the chassis weighs when it's stripped down. I think three people can do it, maybe two very strong ones. If you build a dolly like mine, you can do it all by yourself. I'll be happy to post a picture. My dolly is stout enough to hold 2800 lbs, about 1275 kilos. If you look closely, you can see that each wheel of the dolly is positioned directly below each of the jack points. This ensures that the weight is transfered directly to the wheels. The wooden frame is there only to hold the wheels togther.

As for the suspension, now is the time to redo everything. If you rebuild it now, it will be a little less expensive because all of the stuff is off the car. I had all of my mine powder coated. It was cheap, about $600. The place that I used bakes everything at 400 degrees F to remove grease and oil. Then, the parts are media blasted before the powder coat is applied. I could not have had these pieces painted for that cheap. $600 is a lot of money to spend, but I felt it was cost effective to have the powder coating done. Besides, it really looks great.

Thanks for your offer for help and thanks for posting the pictures of your doors guts. You have resolved my issue, and I thank you for that. Let me know what I can help you with. I'll scan the picture of my dolly tonite and get it to you.

Brian

roland · #15 (**permalink**) 10-27-2003, 09:42 AM

Brian,
quick question. You changed all your bushings I assume. Did you go rubber or poly (I asusme rubber). Any issues fitting them without speialized tools ?
Where did you get buy them ?
Thanks

Roland