Project car - 1989 75 3.0 V6 [Updated 12 November 2021]

[shiny_car]

October 2021 - Part 3

With the pinion gear depth finalised, I started reassembling the gearbox.

This was the cleaned shift rod for 5th/R gears.  The circumferential detent, near the shift fork, was for the spring loaded ball to hold the rod in Neutral, and allow the sausage-shaped interlock plunger to drop into.  Alongside this, the small detent for the ball to help lock in Reverse gear. This detent was not circumferential because the rod needed to push the interlock plunger out into the adjacent (3rd/4th gear) shift rod, locking that rod in N and preventing it from accidentally sliding at the same time.

Further along was the recess for the R gear button switch, that activated the reverse lights.  The tip of the button sits in the recess until R gear is selected.



The workshop manual recommended using AGIP Grease 33/FD bentonite clay grease to lubricate the detent balls and interlock plungers.  Penrite Bentone HD Grease was unavailable, so I used Castrol Spheerol HTB (High Temperature Bearing grease thickened with bentonite clay).

Bentonite clay greases are apparently incompatible with many other greases, so the relevant parts were cleaned carefully of old grease.  I also sourced a new container bolt to replace the one with the damaged head.





After the 5th/R rod was fitted, I reinserted the lower interlock plunger.  In the photo, it's clearly on view because it was not fully seated into the hole.



The 3rd/4th gear shift rod was cleaned for refitment.  There was a circumferential detent for the interlock plungers and detent ball, and a groove for the fork bolt that orientates the fork at the correct angle.



3rd/4th gear shift rod refitted, and the upper interlock plunger.



1st/2nd gear shift rod cleaned.



The final rod refitted, and container bolts with springs and detent balls partly screwed back into position.  I will add sealant before screwing the bolts down completely.



This was a new main control shift rod.  This should help remove any sloppiness in the shift action.

I covered the splines on the main shaft in preparation for sliding it through the new oil seal in the gearbox casing, to prevent damage.





By next month, the gearbox should be reassembled.

No new performance parts to show this month.  Thanks again for looking. 

[shiny_car]

November update!  Gearbox is back together, and rear brakes done.

November 2021 - Part 1

I read various recommendations for gearbox sealant, and decided upon Loctite 518.  It's an anaerobic sealant, so there's no rush to mate the pieces together because it won't start to cure until the parts are joined.  It's a gel, and I found it quite difficult to squeeze from the tube but otherwise easy to spread and clean up.

I also bought Loctite 7649 Surface Primer, to ensure all my Loctite products cure properly.



First pieces to refit and seal were the Reverse gear Interlock Plunger lockout mechanism.





Then, the clutch-speed casing.  From a dry run, I found it easier to sit the intermediate flange and gear shafts horizontally, then support the Reverse idler gear and shift fork by hand, until the gear was supported by its shaft.



Loctite around the mating surface.  Then carefully slid the casing over the shafts ensuring the idler gear and shift fork were in correct positions.





Once mated, I flipped the gearbox vertically.  Loctite to the flange, then slid the diff-speed casing back into final position.  New hardware - including zinc plated Grade 8.8 bolts and wave washers - were used, replicating the originals.







Diff axles refitted, with Loctite sealant.





Differential refitted, with oil on the bearings and shafts.



Then diff cover refitted, using new hardware, all torqued to spec.





Job done!

[shiny_car]

November 2021 - Part 2

Back to the rear brake calipers.

After the paint dried for a week, I disassembled the calipers and removed the masking.  Notice I used the original bolts during painting; they will be replaced with new, longer bolts supplied with the spacer kit.



VHT recommend curing the paint at 93º Celsius (200º Fahrenheit) for an hour.  I did it when my wife was at work  .



I finished cleaning all the caliper parts before reassembly.

The pistons had superficial corrosion/grime around them, which was cleaned with a Dremel polishing wheel and polish.



The self-adjusting mechanisms were removed (refer to the youtube video I linked to, last month).  Some old, gunky brake fluid required removal.  There were also a few spots of minor pitting, but nothing I was concerned about.







After cleaning, they were pressed back into position, using brake caliper lube around the snap ring.





All the parts cleaned and ready for reassembly.  There were three rubber seals to be replaced (and probably a fourth around the external winder that I didn't remove from the caliper); two O-rings for the winders and a seal for the handbrake lever.

I previously purchased a Bigg Red (brand) seal kit, but this only provided piston seals.  After more searching, I determined a Frentech kit for the Alfetta was suitable (eBay UK), and included all the required seals plus more.  The Bigg Red dust seals were slightly thicker and more robust, so I used these.







These were the handbrake lever, spring retaining bracket, and new bolts, after spraying the exposed surfaces metallic grey.



For reassembly, I used these products:
- Penrite Rubber Grease for the O-rings and seals
- Permatex Ceramic Brake Parts Lubricant high temperature grease for metal-to-metal surfaces; also rubber friendly
- brake fluid for the fluid channel O-rings between the caliper pieces



Lubricated and refitted the handbrake lever.



New 25mm diameter Welch plug fitted.  This was flattened and thus locked in position with the press and a socket piece.







New O-ring fitted to the inside winder before refitting.









New piston seal and dust seal fitted; everything lubricated then the piston wound back into the caliper.  The handbrake operates only the inside piston.







New O-ring for the outside winder.





New seals, lubricated, then outside piston wound into the caliper.  In the second photo, new square-cut O-ring seals for the brake fluid channels between the caliper halves, and showing one of the new spacers; these seals were 'wetted' with brake fluid.





Right side caliper bolted back together, with bolts torqued to spec, and handbrake lever spring refitted.  Then secured back onto the gearbox.





Left side caliper parts ready for reassembly.



Handbrake lever, Welch plug, then piston reassembled.





Outside piston reassembled.



Spacers sitting in position, ready for other half of caliper and bolts to be added.



Left side caliper completed.  New zinc plated wave washers, and cleaned original nuts, to secure the caliper to the gearbox studs.





Two rebuilt and painted rear calipers back into position.

[shiny_car]

November 2021 - Part 3

Well...last month I said I wouldn't fall for the unnecessary replacement of brake lines.  But I couldn't resist  .  The existing lines seemed ok, with no damage or corrosion.  However, the outer plastic coating was peeling or scratched on the pipes into the calipers, and also under the bonnet from the brake master cylinder.  I bit the bullet, and found a good source for new tubing, then bought the required tools for the job.

I chose copper-nickel tubing, which is of course ADR compliant, plus highly resistant to corrosion.  It's also relatively soft, making it easy to bend and form the flares on the ends.  The Alfa's brake pipe is 3/16" (4.75mm) outer diameter, and I purchased from Wide Bay Brake Hose Services in Queensland.

https://www.brakehose.com.au/



This copper-nickel tubing was also seamless, whereas the original was Bundy tube.  Bundy tube is made by rolling up a flat sheet of metal then sealing the overlap seam; there's no issue using Bundy, but a solid-wall tube seems more elegant.  This photo shows the cross section of the new copper-nickel versus a piece of original pipe:



This was the new gear I purchased to build new pipes: in particular, the flaring kit with deburring tool, tube straightener, and tube benders.  I already had a tube cutter.  The straightener proved an excellent, useful tool, and of the two benders, the cheap blue version was my preferred after practising with each.

I would describe this flaring kit as an intermediate quality version.  It features a hydraulic ram.  Cheaper kits - though they can still be effective - look fiddly and require manual winding without hydraulic assistance.  More elaborate kits appear overkill for my needs, and better suited for doing this job repeatedly and frequently.  I calculated a total of 18 flares would be required for the new brake lines in my car.  Afterwards, I may never use the gear again!



The Alfa 75 uses two common flares, which I would describe as female and male endings (though they are not intended for joining together).  They are both SAE standard: 'double inverted' flare and 'bubble' (mushroom) flare.  When these flares are secured in position, the clamping force deforms and moulds the flare to create a perfect seal.  Thus, when using new flares, it is recommended to tighten, then loosen, then re-tighten, and do this four times, to ensure the flare is properly sealed, then torque the tube nut to spec.



A bubble flare is created in one stage: the tubing is held in a die, then an adapter (called an OP1 punch) compresses the end of the tubing into the bubble shape.

A double inverted flare is created in two stages: firstly, a bubble flare is made, then in stage two a cone-shaped adapter (OP2 punch) converts the bubble flare into a double inverted flare.



I first practised on a short length of tubing.  This was clamped in the 2-piece die, within a holder.  Then the (black) hydraulic ram pushed the adapter and compressed the tubing into a flare.





Voilà!  A bubble flare, then a double inverted flare!





Now, onto the real thing!  I first made a new pipe for the rear right caliper.  Using some thin rope, I measured the length of the original, and cut new pipe to a similar length.  I reused the original tube nuts.  I read many reminders to ensure the nut is on the pipe before making the flare! 





Starting with a double inverted flare, I proceeded to carefully bend the pipe to replicate the shape of the original.  It's harder than it looks!  Well, at least for the first time.



Before creating the last bend, the end of the pipe needed to remain straight, to fit into the flaring die.  After the bubble flare was made, the pipe was bent into its final shape.







The new brake pipe was then secured in place.  After the initial tighten-loosen steps, the tube nuts were torqued to their final specification, using a flare nut socket piece.





With newfound confidence, I made a new pipe for the left rear caliper.



Two new pipes, from the original brass T-piece joiner to the calipers.

[shiny_car]

November 2021 - Part 4

Final instalment for this month: new brake discs.

The rear discs bolt between the diff axles and spacers.  The spacers had some surface rust.

After degreasing, the spacers were cleaned with wire brushes on a drill and Dremel.  One done, one to go.





After both were cleaned, they were sprayed with Etch Primer then Primer Surfacer.  To avoid building-up a thick layer of paint, I masked the mating surfaces of each spacer after the first coat.  I painted some other parts at the same time.







The exposed surfaces of the spacers were then painted metallic grey.



Right side Tarox ventilated disc, spacer, and re-using original bolts/washers.



Left side parts.



New discs and spacers bolted in position.



Then new brake pads.  These were Ferodo DS2500, which tolerate more abuse (heat) than standard pads, and great for a street car (also fine for some track work).  Lubricating the edge and back of the pads should prevent squeal.  I adjusted the pistons (wound them out), so the pads barely brushed the surface of the discs.  After bedding-in, they should be perfect.



Here we are: refurbished calipers, spacers, new discs, new pads!  Richard Melvin, who supplied the spacer kit and made the pad retaining pins, wasn't exaggerating when he said he made the pins extra long to ease removal! 









That's it for now.  Thanks again for looking!

[Colin Edwards]

Impressive work!!

I fitted Tarox vented rotors to my 75, however your spacer kit is a bit different to the one I used.
You should be happy with the DS2500's.  I have these all round on my 75, though they work better with a bit of heat in them.  Leave a bit of room between you and the car in front when its cold!
There is a mod for the 75 brake balance where more bias is sent to the rears.  My 75 apparently has it.  Some widget adjacent the master cylinder as I recall.  The vented rears will certainly handle it!

[shiny_car]

Thanks Colin. 

I have DS2500 pads on my GT, and used to have them on the 159 Q4 we had.  I like them a lot.

I've seen photos of manually adjustable brake bias units fitted to these cars, in place of the 'automatic' factory limiter.  And my car originally came with nothing, from the previous owner!  My only concern - lack of confidence - is finding the right balance/bias.  The factory setup probably underutilises the rear brakes, but avoids any 'unsafe' rear lockup, particularly during cornering and/or in the wet.

But your suggestion is a timely reminder, and I will do more research into using an adjustable setup, and how to tune it properly (which the need for visiting a test track).

Cheers, Richard

[Alfatango]

Epic thread! Will have to catch up with it all from the beginning. There's a tonne of work that has gone into this.

[shiny_car]

Epic thread! Will have to catch up with it all from the beginning. There's a tonne of work that has gone into this.

Thanks! Enjoy the read: it's been years in the making  lol.  It's been fun so far, and glad I have a project like this to keep me interested.