Title: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 02 October, 2008, 03:59:40 PM After only 37 years rebuilding, she passed her MOT yesterday so I have now had a little drive around and found some problems...
1 How do I keep the oil in the front suspension? It must be 30 or more years since I rebuilt it and I do not recall any sort of oil seals. The instruction book says fill it up till it overflows and that's it but it seems to pump out again in a few miles and I am back to pogoing. Also, what oil to use please? 2 Third gear jumps out. It did on my other gearbox as well. (And on both my Lambdas!) I presume the dogs are worn... Has anyone had them repaired? Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: Scarpia on 02 October, 2008, 04:18:45 PM the oil filling is a mystery to me too. (Mine's a second series with a dual pump on the reservoir). use normal (none synthetic) engine oil
If I pump the reservoir, at a certain moment oil pours out of the pillars and overflows as you say which is a mess and drips down the inside of the wheels. There is no apparent way of knowing when "enough is enough". I have no problem with "pogoing" though. There is a rotating adjuster at the top of the pillar but I never really could tell any difference in driving however I adjust it.My full sliding pillars were rebuilt in Sicily and are effectively brand new so perhaps there are seals worn on yours somewhere letting the oil leak?. At the technical control here in belgium they have a vibrating machine that pumps the suspension and gives a graphic readout and the aprilia supension performed better than many modern cars according to the MOT inspector. ! My gearbox is ok so no experience with repairs I'm afraid. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 10 October, 2008, 09:45:14 AM Mine is first series and so differs from yours internally. I have looked crefully at the drawing in the Handbook and cannot see any seals to be missing or worn and certainly do not remember any.
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 10 October, 2008, 03:44:07 PM David
There are no seals as such to cause leaks.However there is a small spring-loaded ball valve which I believe allows the damper oil to be pumped up through the central rod and out into the space above the damper piston.If this was stuck the oil would steadily accumulate in the lower chambers and spill out of the gap between the two halves of the spring dust covers. If you unscrew the lower cap ( T1 on tavola 17, p48 of your handbook) you should be able to see a slotted screw head by lying on your back under the pillar with a bright torch.Try poking something like a knitting needle (ideally a steel one like Gerry uses to knit your socks with) up through the hole in the above mentioned screw and check that the steel ball lifts off its seat. Or maybe unscrew it and clean it up but I have not tried this with it still on the car. (I assume your "T1" caps are in place and are sound.) The valve components are shown on p 96---Items 38-73165; 38-73170; 48023(the ball); and 38-73163. If this doesnt work or if the oil is leaking from the aluminium cover at the top of the suspension unit the passage-ways in the piston itself may be clogged in which case the only option is a major strip down! I dont think this is likely however. The pump action is the key. When you top up the oil, from the top, as per the handbook most of it will inevitably run out again down through the top bush but hopefully recharging it on the way through as it is porous.The bit in the middle that does the damping should be trapped. If the ball valve was stuck open I would expect the damper oil to drain out when the car was parked rather than be pumped out by the suspension as you drive along. Happy grovelling Ben Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ColinMarr on 10 October, 2008, 04:39:50 PM As I remember it, there are brass ‘nipple’ fittings at the top of the pillars, onto which you screw the hand operated oil pump, which you have already charged with oil. Inside each nipple there should be a ball and spring non-return valve. It was messy, and had to be done every 1000 miles or so, but I don’t remember it being much of a problem. Maybe your balls are missing or not seating properly.
Dropping out of 3rd gear is familiar. The solution in the mid ‘60s was just to fit another gear box of which there seemed to be plenty! Not much help now I’m afraid. But some consolation perhaps from what I have read about with early four-speed Fulvia rally cars, where one of the jobs of the co-driver/ navigator was to hold it in gear! Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: rogerelias on 10 October, 2008, 04:51:05 PM As I remember it, there are brass ‘nipple’ fittings at the top of the pillars, onto which you screw the hand operated oil pump, which you have already charged with oil. Inside each nipple there should be a ball and spring non-return valve. It was messy, and had to be done every 1000 miles or so, but I don’t remember it being much of a problem. Maybe your balls are missing or not seating properly. Dropping out of 3rd gear is familiar. The solution in the mid ‘60s was just to fit another gear box of which there seemed to be plenty! Not much help now I’m afraid. But some consolation perhaps from what I have read about with early four-speed Fulvia rally cars, where one of the jobs of the co-driver/ navigator was to hold it in gear! Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: rogerelias on 10 October, 2008, 04:52:43 PM OOPS 8) PRESSED THE WRONG BUTTON :)
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 10 October, 2008, 05:12:01 PM I think you may have the right diagnosis, Ben. It is not really possible to say when the oil drains out but there is a pair of puddles in the garage. That may well explain why there is no damping action that I can detect. I shall grovel this weekend. I seem to remember that the spring is held by the bottom cover and that dismantling the upper half of the suspension can be done without any special tools?? I shall now scan in the picture in the handbook and enlarge it so my old eyes can see!
David Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: Scarpia on 10 October, 2008, 05:14:57 PM Quote Maybe your balls are missing or not seating properly. that's fighting talk where I come from Colin... ;D Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 12 October, 2008, 08:30:04 AM Diagnosis may have been right but suggested treatment not. I have now inspected some spare bits I have and find the crucial ball valve isnt visible or accessable from below. Thought I should log this in for accuracy of the record. Hope your investigations from the top are successful.
Ben Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ColinMarr on 12 October, 2008, 04:45:19 PM David,
I take it that the aforementioned spring-loaded balls in the filler nipple are snug and comfy. (Sorry about that Scarpia, I didn't meqan to upset you!) For a good and detailed description of the inner bits of the Aprilia front suspension, I suggest you refer to the 31 December 1937 issue of “The Light Car”. This describes how the “small valves (presumably the ones Ben refers to)…allow an easier upward passage for the oil, thus imposing a greater check on the upward motion of the piston than in the opposite direction…(which) controls the upward motion of the wheel due to road shock…”. As I remember it, these valves fit inside a sort of ‘cotton reel’ which is mounted on the rod that goes through the centre of the whole caboodle. Is it possible these have been put in the wrong way round? I don’t think you can get access to these without withdrawing the assembly upwards through the hole in the front wing, for which I think you do need special tools to undo the threaded sleeves down inside the top tube. If you don’t happen to have that issue of The Light Car to hand, I have a spare photo-copy (which seems easier for me to find than my Tax Form P60 for last year!) and I would be happy to post it you. It must be a period copy too, because it’s on 10” X 14”” paper, which is bigger than A4. Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 12 October, 2008, 11:28:31 PM The article you refer to Colin is as you say an excellent description of many aspects of the Aprilia. As fate would have it however I think the description of the damping action is back to front. The valve arrangment within the piston allows the oil to pass down through it relatively easily but restricts its flow more severely as it passes up.Thus as the wheel rises up over a bump the piston moves up easily but its movement back down is slowed down by the damper. Similarly if the wheel passes over a hole the damping action limits the degree to which it drops into the hole. I have harboured this concern for several years now but never had an occasion to unload it before!
Further to my previous suggesions vis-a-vis Davids problem the more I study the design the harder I find it to see any way that oil can escape from the central damper zone. On the first series design the space below the piston and rod assembly appears to be completely sealed off. However if NS---- has a second series front axle the story may be different. The frequent topping up required by the maintenance schedule is for the benefit of the bushes that locate the stub axle etc and slide up and down on the pillar. I think I have only topped up my own car when setting off for Italy. That is 3 times in the last 44 years! Only joking---also before her M.O.T.'s. Incidentally Colin none of my comments about the Aprilia suspension are intended to denigrate the car in any way.I am one of Vincenco's most devoted disciples and would defend the claim that she is his greatest masterpiece to the death. Also I do not subscribe to the opinion that they are fragile.You probably missed the headline in Viva Lancia APRILIA SHOWS INTEGRALE'S THE WAY IN LMC DRIVING TESTS because nobody got around to writing a report but second overall of the Lancias shows they are pretty robust even after 71 years.It also shows yet again how well the suspension works. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ColinMarr on 13 October, 2008, 05:18:24 PM Ben,
O wise and clever man to have owned and enjoyed an Aprilia for 44 years! I am full of admiration and envy. I parted company with my 1939 Lusso in 1969 confident that I could always buy another one. Of course I never did and went on to enjoy Flaminia Sport, Beta 1600 Saloon, Delta 1500, Flavia Vignale, Aurelia B20 and now Fulvia Sport. But I still promise myself another Aprilia – one day. I agree with you about the error in the Light Car article, which is otherwise brilliant. I guess I just read it to say what I expected it to say. I missed the Viva Lancia! article you refer to – which issue was that? Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 15 October, 2008, 03:10:55 PM Here is one picture...
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 15 October, 2008, 03:11:48 PM ...and here is the other
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 15 October, 2008, 03:29:47 PM ...from which we can see that it would appear that Ben's ball valve has migrated from the bottom of the shock absorber rod tunnel (and so visible from underneath) to the bottom of the shock absorber rod itself. My setup is somewhere between the two having a ball valve at the bottom of the rod and a filler for the bottom half of the suspension but otherwise first series bits. There is no communication between the shock absorber and the bottom chamber which serves to lubricate the bottom sleeve only.
Now to the sad bit. I have stripped my shock absorbers (only needed to make two special tools) and discovered them to be filled with woil. This substance used to lubricate Lambda engines before the advent of uncracked heads and seemed to do little harm but left to rot in an Aprilia front suspension it has wreaked havoc. Of the two pistons, one is severely corroded as is its tunnel which is the inside of the kingpin and not clearly removable from the axle shaft (unlike a Lambda). The other one is not so bad. The non return shim/washer that sits on the piston has disintegrated on both sides, hence the total lack of damping that I had mistakenly attributed to oil leakage. I have made new shims (amazing what can be done with a hole punch and a Swiss Army penknife) and restored damping to the better side but the corroded side is weak though I can improve it a bit I guess by using heavier oil. I think I need another axle! HELPP!! Does anyone have one kicking around in the back of the shed? Fortunately the new slidy bits I bought from Cavalllito in 1970 are still OK so wear in the kingpin sleeves does not matter. The internals could be first or second as I am sure it is possible to retrofit Ben's ball valve (bottom left box on 1st series) into the second series lower bush (38-606A etc). Incidentally, I am at a loss to understand what 38-604A doea for a living as it merely floats up and down on the shaft. P.S. I checked out my Lambda front suspension. The shim is on the top of the holey piston not on the bottom as in the Aprilia so it works in the opposite direction!! Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ColinMarr on 15 October, 2008, 08:36:38 PM David,
Ah now I understand – I thought you said your car was first series and when I posted all that guff about screwing on a hand operated pump to get oil through ball valves at the top of the tubes, it must have been confusing. And of course the 1937 Light Car article is irrelevant to you, but it’s still available should anyone else want it. Interesting to see how S2 Aprilia front suspension is like the Aurelia with the ‘hardness/ride’ adjustment lever screw on the top, where the filler used to be. With my B20 the setting I used was first to close that lever down and then undo it by about ¾ turn. I don’t much like the sound of ‘woil’! But pleased to see that you are getting it all sorted. Anyway, nothing to do with Aprilia front suspension, but in response to an off-forum question, here below is a photo of my Flaminia Sport, which I referred to earlier. It was taken in 1970 by the late Roger Perry. Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 16 October, 2008, 03:06:14 PM Correction!! I spent much of last night twisting my brain in topological knots and realised that the Aprilia shock absorber rod is fixed relative to the stub axle whereas the Lambda one is fixed relative to the chassis so both work to allow the wheel to drop freely but prevent it from bouncing up, thus gluing it to the road. I just like to get things right!
Went for a long drive this morning, car feels much better even if it is a little soft on the offside fore. I have now screwed up the rear shock absorbers and will see what that will do... Incidentally, third gear seems to be staying in a bit better too. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 17 October, 2008, 10:00:56 PM David
Thanks for the S2 picture which I've not seen before. On the S1 you can't get the damper rod and piston out from the top. I suspect it is the same for the S2 but can't be sure from the pic. Perhaps you know by now! Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 17 October, 2008, 10:53:01 PM Just read the rest of your post. Clearly the S2 rod etc does come out through the top!
To correct my earlier suggestion, even on the S1 the ball valve is not visible, as I now realise the lower end of the damper rod tube is closed off with a brazed on disc which was not shown very clearly on my drawing. The S2 seems the same in this respect. 38-604A acts as a guide. It is clamped inside the pillar by a ridiculously slim threaded sleeve (38-73075A) and sits on a ledge formed inside the pillar which is incidentally the reason why the S1 damper rod etc wont come out through the top. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 19 October, 2008, 09:35:37 AM But the rod does come out through the top. The threaded sleeve is removed with a tool of 33mm external diameter with four equally spaced 5mm wide teeth on it and the piston then slides out easily. I wonder what happened to the ball valve 38-73xxx shown in the bottom left of the series one drawings and that Ben saw from below??
Please can anyone lend me a piston rod that I can put in my offside suspension while I get mine rebuilt? The nearside works well and gives me hope that a restored piston will fit well enough to save an axle change. Incidentally, before I raid my local motor factors (and Alas! for LSUK) has anyone tried fitting telescopic dampers to the rear suspension and if so what? Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 19 October, 2008, 12:33:45 PM OK I concede the rod comes out of the top for both S1 and S2 once that thin sleeve is unscrewed. See my previous post for conceding that the ball valve is not visible from below.
Still not clear how much S2 you have in your S1 or vice versa.I have an S1 rod you could borrow but do you need the rod or just the piston? Is your rod clamped between the two springs at the top. I cant see these springs in the S2 picture.Do you have the automatic oiler? In fact what is your Ref No (on the plate) and/or Chassis No (on the edge of the bonnet opening).S2 (Tipo 438) Ref Nos start at 10355 and Ch Nos at20077 according to my data). Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ColinMarr on 19 October, 2008, 03:58:52 PM David, Things you might have missed: Under this thread: 12 October 2008 I don’t think you can get access to these (the valves) without withdrawing the assembly upwards through the hole in the front wing, for which I think you do need special tools to undo the threaded sleeves down inside the top tube. Under - Rear suspension: why? how? 7 February 2008 A common mod in the ‘60s was to replace the rear dampers with Koni type telescopic units. The bodge was to cut into the floor pan just ahead of the fuel tank and fit bent sheet-steel ‘towers’ - simply bolted to the floor - to take the top of the damper, with the lower eye on the trailing arm fitting. Purists would object! I wasn’t tempted – I needed the boot space. Colin Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 25 October, 2008, 09:03:05 AM 1/True, special tool described above.
2/I don't fancy cutting holes I think I'll look for some lever arm shockers. 3/Curious!! Ben kindly sent me a shock absorber piston bit it is only 25mm diameter whereas my indisputably first series pattern one is 33mm(?32mm) diameter! Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 26 October, 2008, 10:25:27 AM I wonder if the bits I sent you are from an Appia. My storage system is a bit Haphazard!
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: ben on 26 October, 2008, 02:36:01 PM Ive just checked another damper piston which I believe to be Aprilia 1st series (but from a different axle) and it is the same as the one I sent you i.e. 24.9 mm.
Ben. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: Tony Stephens on 27 October, 2008, 10:57:30 PM From memory (and I last had an Aprilia gearbox to bits about 35 years ago) a cause of jumping out of third gear can be excess end play on the output shaft due to wear in the tail bearing which seems to have a hard life for some reason. Deal with it promptly or the dog engagement will be spoiled which makes it all much more difficult.
The other cause can be that the tail bearing is not secured in the gearbox casing properly. You used to be able to get what appeared at first sight to be an exact replacement, however the recess in the outer track was not wide enough for the little thrust pin and people did not notice, and left the bearing free to slip backwards with the same effect as in my first para. Grind the toe of the thrust pin carefully to fit (if you must!) Anyway that's my verdict, with the usual caveats about failing brain etc. Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 30 November, 2008, 03:49:09 PM I have just taken out a damper piston and I find it to be 32.8mm so I think my axle is 1st/2nd series transition. It may not be the original axle for the car as I rescued front and rear suspension from a near Bristol scrap yard in 1969, reputed to have come off a tourer but the rear was fully independent so that is unlikely. Anyway, shortly after I stripped the cWP so fitted the fresh rear suspension and may have done the same for the front at some time. The new bits I bought from Cavallitto in 1971 fitted it though.
Title: Re: Aprilia NS 1692 lives again! But I need some help please Post by: davidwheeler on 28 May, 2009, 06:38:37 PM Colin Joy sold me a spare axle he had just acquired with a car so I fitted it last week. What a struggle! Two of the fixing bolts sheared off and it took me four days to drill them out and tap the holes (to M12x1.5) It took me a day and several drills to realise that the sheared surface was work hardened but after I had ground them off and got some cobalt drills (heavy pressure and slow speed is the trick) working upside down in the pit I managed it. Off course the holes had wandered off centre a bit but easing the holes in the axle to 13mm took care of that. At least I could put the axle in the drilling machine. I also, foolishly, tried to change the road springs as Colin had said he though there were some broken springs in the suspension. Getting the bottom off is easy (I have a tool made for me 40 years ago which I put between the bottom of the pillar assembly and the floor and lower the car onto it) but locating the thread to put it back on took a couple of hours fiddling - and the spring and bearing surfaces were fine so I did not bother on the other side. I did put in my new (in 1971 but not used since) top end bearing surfaces in, replaced a couple of piston retaining springs and renewed the washers that control flow through the pistons as these are invariably broken. The result is an Aprilia that is once again an utter delight. Hooray!(oorayoorayooray)
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