ATE/Alfasud inboard front calipers - help needed

[Alfasam]

Amongst a job lot of parts I purchased some years ago from a garage clearance was a box containing the component parts of two ATE inboard front brake calipers. The calipers had been dismantled so that the caliper bodies and hand brake adjuster cams could be zinc plated. These parts are in the box looking as good as new, just waiting for the calipers to be reassembled.

As far as I can remember the vendor said that all the parts required to rebuild the calipers bar two small steel locator pins are in the box. However, I cannot be 100% sure as I have not been able to find a technical manual or exploded drawing of how the calipers are assembled.

The problem stems from the fact that there is nothing helpful in either the Haynes or the 1974 Alfa Romeo/Alfasud factory workshop manuals and I have not been able to locate any ATE technical literature either. All the Haynes and Alfasud manuals show is how to change the caliper piston seals and pads - completely insufficient information for my needs.

Other than a set of pictures (see below) put up on a forum by a Swiss enthusiast when he carried out a thorough mechanical rebuild on his 105 bhp S3 Ti I do not have any definitive guide as to what parts should be present and in what order they should be reassembled.

Examining the caliper bodies closely I can see that the hand brake cam is held in place with a small steel pin which looks like it has to be drilled out to take the caliper apart. This must be the missing parts the vendor was referring to. I would have to make another pin from steel rod of suitable diameter in order to locate the handbrake actuator cam in each caliper body.

Has anyone on the forum successfully dismantled and reassembled the handbrake mechanism on one of these calipers? If so, might you be able to point me in the right direction?

Also, does anyone have the ATE technical literature that l presume would show how these calipers are assembled/disassembled to enable repair?
I am somewhat fearful that these calipers may have been a factory sealed part that only ATE could repair at the time. Maybe that's why Alfa Romeo left the details of the internal workings out of the factory issued workshop manual as they did not want their service agents taking them apart.

Any help gratefully received as otherwise I think the calipers may have to be discarded, which seems a shame.

[dralf1965]

I'm afraid i never went as far as removing the handbrake shaft, probably because of the pin. Also it was a long time ago, so can't really remember the order of things. Probably obvious to suggest that you dismantle another set to find out.
Nick

[Kegsti66]

Alfasam, I am sure someone can help.
As Nick says, have you a spare caliper you can carefully dismantle ?
BLS have removed the handbrake parts for racing, so they obviously know the workings. If all the bits are there the calipers shouldn't be discarded.

[dave.armstrong]

It is a while since I did mine.

I have looked on the fische but that is obviously where Haynes got their diagram from so it does not help.

Sorry

[Alfasam]

Thanks to everyone that has tried to help with this problem.

I agree that the suggestion to dismantle another caliper is probably going to be the only way of discovering the innermost workings of the handbrake mechanism.

Accordingly, I have now obtained another used caliper so I can set to and do just that.

Hopefully, I will find time over the holiday period to take the caliper apart carefully and make notes/take pics to post onto this thread showing exactly how it goes together.

Watch this space.

[bert308]

Here is a facebook album with pictures and comments about the rebuild of very similar Porsche 914-6/Ferrari 308 calipers:
http://www.facebook.com/72240238192/pho ... 3740938192

[Alfasam]

Thanks for the heads up Bert308.

Will check this link out and see what I can learn from it.

[Spacenut]

Has anyone on the forum successfully dismantled and reassembled the handbrake mechanism on one of these calipers? If so, might you be able to point me in the right direction?

Hi Alfasam - sorry to resurrect this thread if you already know the answer, but I have recently acquired 3 pairs of ATE front calipers as back-up for my as-yet unresolved Budweg caliper leak problem. Anyway, I've successfully dismantled one caliper and can confirm that the parts as laid out in the pictures are in the order they go together.

Please note - the locating pins you refer to are two roll pins inserted into the inner caliper body below the piston. They stop the brake pad from dropping out of the bottom. I noticed in the image that the pins were not present. The holes for them should be in the casting, hopefully they haven't been snapped off. That is all that is missing, so do not, repeat, do not scrap them!!!

What I did was this:
1. Split the caliper by removing the 4 bolts holding the two halves together
2. Use the 7mm hex adjuster to wind the piston out as far as it will go (the adjuster rotates via a worm the threaded shaft which screws into the back of the piston)
3. Assist the final removal of the piston with Mole grips - the close fit and seals mean the piston won't drop out of its own accord
4. Remove the circlip at the base of the threaded adjuster shaft. This allows the "top hat" cover and spring to be removed
5. Pop the shaft out of the bore. It has fluid seals to stop the grease from the handbrake mechanism migrating into the brake fluid chamber.
6. The steel pin that looks like a Tic Tac transfers the rotation of the handbrake shaft into the linear motion of the threaded shaft, with the worm drive taking up the clearance. The Tic Tac shaft engages into a cup recess in the handbrake shaft
7. Remove the circlip at the base of the handbrake shaft and withdraw from the caliper body. There are a number of seals to stop the grease getting out, as shown in the pictures.

That's the inner caliper. The outer one is even easier to dismantle...

1. Remove the circlip on the Allen key adjuster if fitted (it should be, otherwise you cannot retract the piston with the adjuster)
2. Use the Allen key adjuster to wind the piston out as far as it will go.
3. Using suitable packing, I put the caliper in a vice so that the adjuster pushes the piston out of the caliper body (you could use Mole grips again if you like). You are only overcoming the resistance of the piston seals so it should require little persuasion to get it out.

Reassembly, as all the best texts say, is the reverse of removal.

I hope this helps a bit. I haven't figured out how to remove the inboard hex adjuster, and it looks like these items weren't removed from your calipers either, so maybe they don't need to come out. There are no clips holding them in, they look like they might pop out...

But it's those pad locating roll pins on the outside of your calipers that are missing, nothing else.

Lauren

[PETROLHEAD]

All good info there, but as bert mentions earlier, the same caliper was used as a ferrari rear i gather, so you might well find more details that way.

They are a fiddly pain, but it is still surprising how little is known/published about them, so lets hope this thread changes that.

[Spacenut]

Agreed! I searched all the usual sources, Haynes manual, Alfa workshop manual etc. to no avail. The caliper I've had apart has a busted roll pin (the one that limits the handbrake lever travel) and was therefore a "freebie". That said, I have made some progress drilling out the broken stub, and the signs are good that I can rescue this pair as well.

I've looked at the Fezza 308 calipers, they are cable operated but the handbrake lever is vertical, not horizontal like the Alfasud. The Vo-Po 914 and Alfetta GTV use the same design. Almost certainly the same internally. I think I saw some disassembly instructions for the Alfetta calipers on AlfaBB, but that's about it...

Out of interest, the gold finish on Alfasam's calipers look very nice, are they electroplated or painted? I might consider getting one pair electroplated as long as I can have them in gold!

Lauren

[KevJTD]

I do recall asking BLS Tom about the Alfetta rear caliper and Sud caliper some years back as they looked identical to me but he reckons there was a subtle difference between the two but couldn't recall exactly what....so that's no help at all I know!

[dave.armstrong]

I do recall asking BLS Tom about the Alfetta rear caliper and Sud caliper some years back as they looked identical to me but he reckons there was a subtle difference between the two but couldn't recall exactly what....so that's no help at all I know!

I love either wine or beer on a Friday night! Don't you Kev?

[KevJTD]

I do recall asking BLS Tom about the Alfetta rear caliper and Sud caliper some years back as they looked identical to me but he reckons there was a subtle difference between the two but couldn't recall exactly what....so that's no help at all I know!

I love either wine or beer on a Friday night! Don't you Kev?

garbled messages, my forte

like a broken pencil...pointless

[Spacenut]

Final piece of the jigsaw puzzle was revealed today - how is the inboard (7mm hex) adjuster located in the body?

I started looking at the 3 pairs of spare calipers I have, to see which one I should get media blasted first. The number 3 pair cost me nothing, so I have been dismantling them to see how they work. The number two pair seemed like a good bet, until I realised that one of the bleed screws was missing and the bore was rusty.

So the number one pair was selected, but while I was winding back the inboard caliper, the whole adjuster came out, oil seal and worm drive. Looking very closely at the number two set it became clear that there is a small internal circlip which engages into a annular groove in the bore, which retains the adjuster and the oil seal in the bore. Clearly someone had tried to force the adjuster in the past and popped the circlip out.

The final mystery is how to remove the circlip without putting the adjuster mechanism under enormous strain? It isn't a proper circlip with needle holes in the ends - there isn't enough room. It is just a sprung steel wire. But at least I know how to fix the number one set now

Lauren