Augusta progress

[Mikenoangelo]

Lots of fiddly work involved to sort out the rear shockers.

First the saddle brackets for the connecting link. Hard to hold them to mill away the old welds on the bracket but a few clamps and a length of ex Stanley Steamer front axle tube did the trick (147. The shockabsorber arm ends were machined to take a new sleeve for the rubber bush (148).The arms had been severely fettled in the past and one had much welding done so rather than just welding the sleeve in place I copied a Hartford method, making a bracket fitting around the sleeve and bolting to the arm (149).The arm has three leaves held together with rivets, avoiding which meant making the bracket a bit longer than I wished. The trick with making multiple identical parts is to sandwich them together and machine them in one go (150). Lastly the bush sleeves will be welded into the bracket - but only when lockdown lets me out to visit the welder.

Then that strange offset link. I didn’t think I could bend the strip neatly to copy the design seen in David’s pictures and spent a while  pondering how I could simplify the job, eventually coming up with this design which just involves drilled steel strips bolted together with spacers between to provide the necessary 16mm offset between top and bottom bushes while still giving clearance between the link and the lower part of the floor and frame of the body (151).

I think the  position of the shock absorber and its connection to the axle are compromised by the offset and lack of lateral float. Perhaps the existence of two designs of the link indicates a recognition of this as a problem by Lancia.

On our car at least, the previous bodged repairs to the saddle bracket suggests that there are forces which the saddle bracket does not like. Davids’s second photo shows the wear to the inside of the link which must result from side thrust. I assume there are some side forces when one wheel goes over a large bump which are taken  by flexing of the arm and in the metalastic bushes in which the link articulates. The original offset links are made from something  harder than  mild steel and probably are just as stiff as my version. I am replacing the metalastic bushes with polyurethane inserts and will make sure they have enough side float on the inner sleeve to allow a bit of movement.

Mike

[Dikappa]

I love that machine work!  Makes me feel soo clumsy....

[nevillesponge]

Mike, that’s impressive! I hadn’t given thought to the wear being based on stresses. I’d just assumed (perhaps naively) that it was because of having no bushing left due to degrading and general movement whilst driving. Your suggestion makes perfect sense, so I’ll need to keep a close eye on my brackets once I’m out on the road again.
David

[Mikenoangelo]

Today while making connecting plates for the rear shock absorber links I had a flash of inspiration on how to hold the links to machine the rounded ends and smooth the sides.

Very simple in the end. Using the 300mm  rotary table with the stack of plates lined up with the centre of rotation of the table I found that a combination of two (sacrificial) blocks of aluminium bolted down to the table and then clamped together with a large “G” clamp made an excellent vice to hold the stack of plates. Face down to round the ends and sideways on to skim the width, with short lengths of 6mm and 10mm rod in the holes to keep the plates lined up. I had drilled the plates in a stack so that measuring and marking was only needed once.

So I learned something new which makes the rotary table much more versatile.

Mike

[Jaydub]

 
 Nice Job Mike, but only simple, as you put it, if the have the machinery and knowledge to use said machinery!
 Clever stuff as usual from you.

[Mikenoangelo]

Slow progress on the rear shock absorbers. It turned out that both were well worn, the wooden friction discs being so thin that the protective rims on the blade like arms were nipped together and the arms themselves squeezed out of parallel. One shock absorber was extremely tight until freed off by cleaning the discs.  

The Augusta friction shock absorber relies on a very strong coil spring to clamp the arms and friction discs, the degree of clamping being determined by a nut on the bolt holding it all together, the nut is locked by a split pin and therefore not readily adjustable. I struggled to find a means of setting the friction to an acceptable level because the springs on both shockers are so strong that the slightest compression of the spring virtually jams the movement of the arm. Clearly something is wrong, perhaps a previous bodge, as one of the clamping bolts, which should have a peg/notch arrangement to restrain the head of the bolt, had been swapped for an ordinary hex bolt and although one shocker had a spacer on  the outer end of the boss on the body of the shocker which acts as the bearing around which the arm swings, the other did not.

I found when taking them apart or re-assembling them, a plate bolted across the chassis side of the cast base will hold the spring compressed so other bits can be removed or fitted. In place on the car of course the base is bolted to the frame so the spring is controlled and the arms can be detached if needed.

Looking through a box of Andre Hartford bits, it struck me that I could dispense with the Lancia coil spring and use readily available Hartford parts, along with a new centre bolt, a Hartford star shaped dished spring and a few other bits to convert the Lancia design to something of a Hartford which would be a much better option.

Pictures 155 to 157 show the original and replacement parts. A new bolt with peg to stop the bolt turning, a tubular spacer to replace the spring, a slimmer spacer (recessed to take a clamping nut to hold the bolt to the base) , the original Lancia dished washer, the Hartford star spring, the tension adjusting nut (with indicator needle) and finally a locknut. The recessed spacer is needed as it acts as the bearing for the outer disc and arm, the centre boss on its own being a bit too short. Note the tension adjusting nut has to be 28mm AF to fit the Hartford indicator arrow and also needs a short spigot on the inner side to adapt the 14mm bore of arrow and spring to the 12mm of the Lancia size bolt. The locating peg hole was drilled 4mm and the peg made from a short length of 4mm drill shank loctited in place.

The original wooden friction discs were under 4mm thick but after a bit of measuring I found that replacing them with 5mm material would work, although needing 0.5mm or 1mm packing between ends of the short arms where they are bolted to the base. With this the arms and discs are parallel and the protective rims on the arms are just slightly separated. Photo 158 and 159. I suspect the originals were about 4.5mm thick but that was not available.

The available wooden discs for Hartford shockers are of a different size to the Augusta version but I found a supplier who can laser cut 5mm oak to suit and these fitted perfectly. I have a spare set if anyone needs them. They need to be soaked in oil before fitting and the metal faces of the arms greased.

The shockers can now be adjusted simply and they feel to operate very smoothly with only moderate “stiction”. Now all I need is a visit to the welder before it can all go back together.

We know Lancia was an individualist but I do wonder whether the unusual design of the Augusta friction shocker had something to do with getting around patents?


Mike

[Mikenoangelo]

While the shock absorber repair was held up waiting for the welder’s attention I turned to the back brakes, pretty much the last major bit of the car, apart from the rear axle itself, that I have not gone over.

The right (offside} brake seemed to bind very slightly and the handbrake lever on the back plate was very stiff and reluctant to release fully. So off with the drums - easier said than done as I do not have a puller which can engage with the wheel studs so had to resort to the correct method after making a disc to screw onto the male thread (58mm x 2mm pitch) on the centre of the hub. A fiddly job, having no possibility of trying the hub into the thread as I cut with a single point tool in the lathe, I first made a male threaded dummy , testing the final cut by screwing on one of the hub bearing covers from the front wheel. The threaded dummy was then used to get the final size for the internal thread of my puller disc. The  difference  between being too tight and being just right is only about 0.001” depth of cut and once the work piece has been taken out of the lathe chuck, it is almost impossible to put it back in to make another cut. I was worried that it would not fit the thread on the hub but luckily it did, very nicely after I had cleaned up the hub threads.

Removing the hub from the tapered half shaft takes quite a strong pull, but with plenty of tension on, a sharp whack on the hub flange and, with a loud crack it came off. I always leave the nut loosely in place when I do this so the hub and brake drum do not just drop off or worse fly across the workshop.

The seizure of the offside brake turned out to be due to corrosion of both steel and aluminium at the lower pivot of the brake shoes which prevented full articulation of the brake shoe. A good clean and some grease will sort that out. The linings are in good shape and the rubbing surface of the drum perfect, evidently having been skimmed true.
The linings have been bonded on rather than riveted as original as although this is normal for modern new shoes, it is a bit suspect when relining an old, possibly corroded aluminium shoe. However they look completely sound.
.
The drums are an amazing example of Lancia’s attention to detail - and complexity. The main part of the drum is aluminium, attached to the hub flange by 24 copper rivets. The wearing surface is a cast iron insert onto which the aluminium is cast. The completed drum was balanced,  the stamping  - equilibrato- on the outer face of the drum being lined up with a balancing steel strip n the inside. Little wonder the brakes work well but no doubt reproducing the hub and drum would be a nightmare.

Mike

[Mikenoangelo]

Back to the shock absorbers, now welded ready to fit. I decided to replace the original worn out metalastic bushes with polyurethane turned from a length of rod of 80-90 Shore hardness, which is similar to tyre rubber. The tricky bit, having made new outer holding sleeves and fitted these to the shocker arms and to the saddle brackets, was to machine the polyurethane to size to achieve a tight push fit into the outer sleeve and a running fit on the inner sleeve which surrounds the  clamping bolt on the offset connecting link. A bit of experimentation showed that making the polyurethane bush about 1mm oversize gave a very firm push fit into the steel sleeve when the inner hole had been drilled. More difficult was to find the right size to drill the bush  for a running fit on the inner sleeve as this is hugely affected by the squeezing of the bush when fitted. I found the easiest way was to drill the bush about 2mm over the target size and then machine the steel inner sleeve to suit,  a 17mm drill suited a 15mm steel inner. Rubbery polyurethane can be machined but needs very sharp lathe tools and drill bits to cut cleanly. If all else fails, put the job in the freezer and when cold get it machined before it warms up!

I made the bushes just long enough to form a buffer to stop the outer sleeves from contacting the inside of the connecting links, and with a little side clearance to allow for lateral movement of the shock absorber arm relative to the axle.

Mike

[Mikenoangelo]

I removed the rear brake back plates to clean up and paint and to sort out the brake cylinders, which although not leaking onto the shoes showed signs of seepage around the pistons. These were rather difficult to remove but responded to a little encouragement with a shot of oil applied by grease gun via the bleed screw. I was a little confused by the bleed screw which had the usual type of screwed bleed insert to connect drain pipe for bleeding but it turned out that the actual bleed valve was not the inserted screw but the threaded fitting it was screwed into which itself had to be turned to pass fluid.

I cleaned up the bores of the cylinders but found that the middle part of the bore, just where the piston seals make contact when the brakes are off, were quite pitted, probably beyond what could reasonably be honed out. Crud and corrosion at this point was what stopped the pistons from being removed by pushing them through the cylinder While pondering this I pressure tested the  cleaned up pistons and seals with the oil gun and they were able to hold pressure without leaking, however better safe than sorry so I ordered a set of cylnders from Power Track Ltd  brakeinfo@powertrackbrakes.co.uk who were very helpful, although the price was eye watering. They are made in Germany and are the bronze version as sold by Cavalitto whom Power Track also supply. A bank raid is envisaged.



Mike

[JohnMillham]

I ordered a set of brake cylinders from Cavalitto one afternoon and they arrived just before noon the next day. Postage cost €20, which I thought was pretty good service.

[Mikenoangelo]

Brake cylinders arrived and all back brake parts cleaned and painted ready to refit, along with the refurbished shock absorbers.

Back to the vibration issue which seems to relate to transmission  not engine. Being unable to try the car on the road I now have it supported on axle stands and props under the chassis and can run it after removing in stages, wheels, brake drums and even the propshaft to eliminate their influence.

Conclusion is that although the wheels do have an influence, the main source has to be the propshaft as, only when this is removed does the vibration diminish. There remains some engine vibration but nothing emanating from the clutch or gearbox as declutching or putting the gears in neutral makes no difference with no propshaft in place. Declutching  stops the vibration when the prop shaft is fitted .and the vibration is related to propshaft rpm  not engine rpm as can be seen by running in third gear rather than 4th. Watching the propshaft and feeling the back axle casing while running at vibrating revs showed no sign of anything amiss and I had already found the propshaft (at least at its midpoint) appears to run very true.

Having fitted new fabric discs and had the propshaft balanced the only thing I can think of is some problem with the three legged locating spiders which centralise the fabric discs to the gearbox output and pinion input shafts. I had already changed the centre boss of one spider to improve the fit to the pinion shaft but now took a very critical look at the exact position of the three bolt holes which connect to the propshaft and discs.

It is not easy to measure the concentricity of the bolt holes to the centre of the unit but on one spider a bolt hole was about 1 degree displaced on the circumference, and on the other spider the centre boss had a slightly loose fit to the pinion shaft boss. Neither spider seemed to be original so I decided to make a new pair which I hoped would improve the accuracy and fit.

Another interesting lathe and milling machine project starting with two squares of 3mm steel centre marked and bored 31mm in the four jaw chuck of the lathe. These were  mounted centrally to the rotary table, using a 31mm dummy centre fitted over my 8mm centering spike so that the bolt holes could be drilled. Then with the plates bolted down with a couple of washers under each bolt for clearance I cut slots to form the flanks of the three arms and the three sides of the plates, finishing off and liberating the spiders by rounding off the ends of the arms. I only had to position the cut once for the arms and once for the side of the spiders as rotating the work piece through 180 or 120 degrees automatically positioned the cuts precisely. I  could of course have had the new spiders laser cut rather than mowing them out myself but I am impatient to see if they work and enjoy the challenge.

I then made hat shaped centre bosses for the spiders, boring these to get a good fit onto the gearbox and pinion shaft spigots and screwed these to the plates with 5mm CSK screws which also retain a 2mm thick steel cap on the boss.

I am not convinced that this exercise will cure the vibration but I’ll soon find out!

Mike

[Mikenoangelo]

Still there dammit although possibly reduced. With the car still raised on axle stands front and back with the wheels in place this vibration is at 2500rpm upwards in top gear, and does not occur at the same revs in third or in neutral, although the engine is not as smooth as I would hope. What next? I seem to have done everything I can think of which can be done without a proper vibration analysis. A road test will have to await an essential journey which is pretty rare just now, my modern having done under 400 miles in the last 12 months.

I’d like to get the engine balanced but am reluctant to get this done now as I am thinking of replacing the crank and rods if, as seems possible, new cranks are to be made.

Mike

[JohnMillham]

Are you running it with the wheels on?

[Mikenoangelo]

I've tried it with and without wheels and even with the drum/hubs removed. The result is the same, it is actually slightly smoother with the wheels fitted -presumably their rotating mass damps the vibration. The wheels have been balanced and seem to be well balanced if I put them on the front.

Mike

[Kari]

I am sure you have checked the shaft that it's not bent and runs true, at the ends and in the middle. There in not dirt inside the tube? Any balancing weights in place?

The flexible disks could be checked for inbalance if an adapter is made to enable to run them on a hand held power drill. Any inbalance is instantly felt! The 8 mm bolts, their nuts and washers should be the same mass.

Perhaps there is a difference, if the propshaft is running with load or no load.

Are the wheels dynamically balanced? Static balancing is not sufficient.

   Karl