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Rear Suspension

Suspension differences - 'Sud and early Sprint to 33 and later Sprint


Parts known to be different

Rear beam axle
Panhard rod
All four watts linkages
Rear shock absorbers and mounting shackles
Rear drum brake
Brake backplate and stub axle assemblies
Handbrake assembly and cables

The majority of the rear suspension has been significantly modified.. 

The 33 rear has drum brakes, with twin leading shoes and cable operated handbrake assembly mounted together with the rear hubs. The brake drums are the location of the outer tracks for the rear taper type bearings. A single cable comes from each brake assembly, pass along the front watts links, and then meet up to a central adjustable bracket mounted just rear of the subtly different handbrake assembly. The beam axle is made from large diameter steel tubing, with the spring lower seats, watts linkage and panhard rod attachment points welded to it. It is considerably lighter than the earlier welded pressed steel assembly. The brake backplate and hub assembly bolts directly onto the ends of the beam axle. The panhard rods and watts linkages are similar design to earlier, but with detail differences to lengths and shapes. The rear suspension must be changed complete. It is important to note that series 3 Alfa 33s have a different watts linkage arrangement to everything else, which makes them physically impossible to fit to any other mark of Alfa. More of that later The rear shock absorber mounting shackles are different. The brake setup of the later cars incorporates a dual circuit with a diagonal split, ensuring even braking if one circuit fails. The rear brakes are fed though a dual biasing valve, which is modulated via a linkage on the panhard rod. This normally rusts solid though, it is an Alfa after all.


The transplant itself


This should have been a very easy job, in theory requiring a straightforward transfer from one car to another. Wrong, as you will read. I have started the report with the problems because I believe that this will help others avoid some irritating pitfalls.


Alfa 33 series three rear suspension problems


This was a maddening problem, to say the least. I had bought the donor vehicle from an Alfa specialist, after having told him exactly what I was going to do. I had to buy 'blind' as I didn't have the time available to go trawling round for a donor once I was there. I trusted him to get me the correct donor car, and all I can say is it was a mistake. The first clanger was when I went to get the rear suspension off the donor car. As most of you probably know, 'Suds, Sprints and series one and two 33's all have a rear suspension system that has a beam axle that is located by two arms going forward, and two arms going backwards. As long as you change the whole lot, it fits in exactly the same location points. What has the series 3 Alfa 33 got? It has all four arms going forwards and attaching in front of the wheels. This renders the series 3 rear suspension totally unusable for earlier cars. No, sorry, not completely. The panhard rod is the same as the earlier 33's, but that is all.

\$#**#$ were my words at the time. As this was my first job to be tackled, it did not give me a lot of confidence. I was soon on the phone to berate the guy and ordered the correct set of bits from him. Once I got the series two parts, it all bolted onto the Sprint like clockwork.


Rear Suspension replacement procedure


Assuming you have the earlier 33 or late Sprint type suspension, installation is simple.

By fitting the rear suspension from the later car you are converting to a handbrake acting on the rear wheels. If for some reason you are only converting the rear suspension remember to disconnect the handbrake cable from the front calipers.

I strongly recommend that the car be lifted front and back, and placed on sturdy supports for suspension swaps. I used two sets of axle stands, one stand under each jacking point, but before you use these points, check their integrity. I have seen a number of Suds and Sprints where jacking on these points has just lifted the jacking point through the floor of the car! If they are weak on your car, my suggestion would be to question the value of doing the conversion - get your chassis welded up before you start anything like this.

Obviously you would start by removing the entire rear suspension, complete with all watts linkages, panhard rod and brake lines. In addition, remove the passenger seat (trust me!) and the centre console type affair that surrounds the hand brake. Disconnect the handbrake cable from the handbrake lever, then remove the entire handbrake lever assembly.

Generally, you are going to find that the rear brake proportioning valve is rusted solid. Whether you bypass it or continue to plumb through it is your choice. I ended up replacing the rusted unit with an original Alfa unit, which was not too expensive. I will discuss braking other than the handbrake under the braking section, and deal solely with the suspension side here. It is not a problem to remove and throw away the sort of spring rod that sits on the panhard rod that is supposed to operate the bias valve if you know it is seized or you will not be using the bias valve.

The beam axle complete with brake drums, shoes, cylinder, handbrake mechanism, handbrake cables, watts linkages, shock absorbers, springs and panhard rod can be lifted as a built up assembly into the rear of the car. When fitting AVO adjustable shocks (good quality), turn the base of the shock so that it sits with the adjuster knurled wheel facing inwards. Do not fully tighten any of the suspension bolts and nuts though, as this must be done with the weight of the car on the wheels. A helping hand guiding the shock top mounts and upper spring platforms into their correct positions in the turrets will stop you inadvertently lifting the body with the shocks. Once it pokes through, get the top rubber bush and nut on it quickly, and it will help you position everything else.

Remember to pass the handbrake cables through the front watts link loops (if they are still there), and don't forget the two brackets for the handbrake cable that go on the front watts link mountings. Note - the one on the same side as the exhaust (left hand side) goes on the outside of the mounting bracket, the one on the other side goes on the inside. Clip the handbrake cables into the clips and then push them through the two oval slots in the centre tunnel so that they go into the car. All plastic bumper Suds and Sprints will have these holes already, covered by plastic covers or fibre tape. Inside the car, you'll see the two cables poking up through the floor, and there will be holes in the carpet at that point, another rectangular hole just in front of it for the centre console mounting screw, and then a another sort of triangular hole in front of that. The triangular bracket from the donor car will bolt straight to that, trust me. If you cannot find the holes, push down with a small screwdriver, and eventually you'll find them. They are often completely filled with underseal, and then painted over, so it looks like they aren't there, but trust me, they are. Before you connect the triangular bracket to the cables, remember to put the two rubber grommets on, with the arrow on the top pointing forwards. Then just connect all the brackets and the handbrake adjuster and lever up, and bolt them down to the floor pan - the bolt patterns are the same. Pulling the hand brake on and off a couple of times will help you get everything in position a little easier, and stops the fight against the cables.
 sprint041.jpg (58448 bytes)  sprint040.jpg (53772 bytes)

Remember to tighten all the eight watts linkage bolts and the two panhard rod bolts, plus the shock absorber shackle bottom nut and the locknut inside the car. If you had forgotten to tighten the bolt that holds the bottom of the shock to the shackle, it can be done now, but it is not easy. Good luck!

Remember to tighten all the eight watts linkage bolts and the two panhard rod bolts, plus the shock absorber shackle bottom nut and the locknut inside the car. If you had forgotten to tighten the bolt that holds the bottom of the shock to the shackle, it can be done now, but it is not easy. Good luck!


Some notes about the rear suspension


Remember when fitting the watts linkages to put them on the right way round otherwise they may rub on the tyres.

The shock absorber shackles on my example are badly rusted, and I suspect that that may be normal. I will be replacing them with new ones.

While you have the watts linkages and panhard rod off, that is a good time to replace the bushes. If you are on a tight budget, the ones on the short (rear) rods are the first ones to be worn out. Replacing the bushes yourself is quite easy if you have patience, access to a big vice and some largish sockets or gas barrel. I hope to put a picture of the setup I used to install them somewhere.

The front watts linkages have, part way along their length, a welded on loop of metal which the handbrake cable passes through. The loops may be rusted through, or at least worn, and there may be a groove worn in the linkage itself where the cable rubs against it. The rusted through loops can be replaced by strategically placed cable tie wraps (marvelous things!), but I suggest filing off the remains of the loop if there are any sharp edges. The groove in the linkage may need careful study - if it is too deep, it may have weakened the rod. If it is not, then try and protect it with primer and underseal.

When you are getting the bits off your donor car, remember these items, to save on head scratching later: On the forward mounting points of the front watts linkages, trapped by the through bolt and nut, are little brackets that hold the handbrake cable. Inside the car you will have to rob the entire handbrake lever assembly complete with the three bolts, adjuster, a triangular bracket held on by three bolts, and the two grommets that go over the cables where they pass through the floorpan.