I picked up a rear end from a 1990 Volvo 240 with a 3.73 ratio and will be putting it in my 24 valve Ascona wagon.
I drilled the axles to a 4x100 pattern today (5x108 is stock) and a G80 locker carrier will be here tomorrow.
As of now, I'm leaning toward using the Opel spring buckets with adjustable arms and a torque arm going up to the Opel center joint mount. This will allow the Opel shock mounts and panhard bar mounts to be used.
Another option was sent to me by dsmith which needs more looking into. In that GT install, the Opel springs were mounted on the Volvo trailing arms and the arms matched up to the Opel front mounts. Two links from the axle to the training arm stabilized the axle. Shock and panhard mounts were relocated.
The brake system on the rear end needs replacing. The Volvo e-brake uses brake shoes on the inside of the rotors and both were in real rough shape. Rock Auto and Advanced auto will have all the Volvo brake parts here by Thursday.
I installed the Eaton G-80 locker today. When one wheel spins 100rpm or more than the other, the diff locks and both wheels pull until you back off the pedal. When you go over 20 mph it stays one wheel drive. There are mods that can be made to the unit so it will stay locked to a higher speed. I'm going to wait and see how it performs before modifying it.
Brake rotors fit on my Smithy Drill/Mill/Lathe so I was able to open up the rotor I.D.
While I'm waiting for the brake parts to arrive, I will be pulling the Opel rear end out. Using the Volvo trailing arms is looking more promising...
Out with the old!
One was to remove a rear end when you are working alone.
In with the New
Temporary fitting shows the Volvo 240 rear end fits nicely.
The Volvo trailing arms will line up close to the Opel arm mounts. The shocks will be able to be mounted to the rear of the trailing arms and the Opel springs will locate in front of the axle on the trailing arms.
The rear bushings in my axle were shot. I ordered poly ones. Once they arrive I will be able to get further into the mounting.
Here is a pic of this install in an Opel GT:
The axle is all clean and POR'd. A test fitting showed me that the Volvo trailing arms can be used.
After installing poly bushings at the rear of the trailing arm, they were attached and with little alignment, adjustable rod ends will line up with the Opel mounting location. The springs will line up in front of the axle and with spring hats installed on the arms, they will sit ~1 inch higher than original. I'll need to either use a shorter spring or cut one down.
Lower shock mounts will be on the back of the trailing arms.
Adjustable links will go from the axle mounts to the trailing arms and a new adjustable panhard bar made up.
Of course the wheels I am using hit the axle so I had to get longer studs and a 10mm spacer. I opened up the 4x100 Honda spacers to fit the axle today so tomorrow the wheels will go on and I can center the axle and get accurate locations for the rod ends and spring hats.
The link and panhard components will be here Thursday.
Shock aligns with trailing arm spring pad.
Locating the coil spring perch.
3/4 inch Rod end with a 5 inch long Threaded steel sleeve from Speedway motors.
Centering the wheels
The spring hat sits on the top surface and is under the stock upper hat. After cutting off the Volvo body mount, the rod ends fit into the Opel body mounts with spacers taking up the slack.
Found a surprise on the stock arms.
Rear end is roughed in place.
Stopping power; Volvo rear disc brakes installed.
The wheels are centered. The panhard bar and sway bar are in place.
Pluses for the Volvo 240 rear end:
- Dana 30 diff. Same as a jeep. many ratios available
- Parts readily available
- G-80 locker on '92 204's fits right into older ones
- Disc brakes
- All welding is done on the Volvo trailing arms (new ones are ~$70.00)
- Trailing arms and brackets for links are on the same axis
- Fully adjustable in all planes
- Same width as Manta/Ascona diff
- Front of trailing arms are very close to Opel body mounts
- Uses stock Volvo sway bar
- Volvo 240 diffs are common in salvage yards
Minuses:
- Axles need to be drilled for 4x100 bolt pattern if using Opel rims (5x108 is stock)
- Springs need to be cutdown (recessing the springs into the trailing arms will eliminate this) Note: After driving the wagon with this setup, the rear kept hitting the bump stops when hitting a bump in the road. Stiffer springs or recessingthem into the trailing arms would fix this.
Here is the way I initially set the upper arms up. After discussing this with several opelgt.com members, I decided to go to a true 4-link setup. The upper link was moved and mounted on the frame like in the drawing below.
There's some interesting info on the Manta 400 suspension (and pics) here: Ascona/ Manta 400/commo Rear Bottom Link Angle. - Basic Tech help - Opel Manta Owners Club
But Wait, There's More!
Manta 400 upper links comments from a post on the Opel Manta Owners site"
The cars that the setup was used on before it was robbed for the 400's were hardly renowned as great handling machines!! (the vauxhall victor we have which is on ebay at the mo incidentally, was hardly a great handler!)
The upper links are so short that the diff nose is pitched wildly for very small amounts of suspension travel, and in roll, the whole lot just binds up without the very big, very compliant rubber bushes. I dare say if you fitted polybushes the axle would go solid in roll!
I did do some 2d drawings of the setup on Curt's car before we fitted it, just to check diff nose pitch during travel, and with the much longer upper links that we used it is much reduced (but still very noticeable, just not horrendous as with the commo setup!!)
I guess this is why Opel used the long upper arm setup on a lot of the rally cars!
re. Curts car handling, from what its possible to tell on the road, it handles very well. Rough surfaces during cornering don't upset it AT ALL (which is one of my pet "requisites" for a modified road car) it just grips and goes. It just needs a lot more power now!! A std XE on throttle bodies is nowhere near enough to test the potential of the car! I reckon around 275hp normally aspirated XE would do the trick!
PS no rear roll bar.It has the mounts in place for the rear mounted 400 type bar, but none fitted at the mo as I advised against it. There is a little roll, but don't make the common mistake of thinking that any roll is bad, its only bad if it upsets the tyre contact patch, other than that it doesn't matter a jot! The car has a std manta GTE front bar fitted, and feels spot on. The progressive springs on the rear keep it nice and soft at initial movement, keeping traction, but stiffen up nicely under heavier load, all very progressive though.
If the links are too short, the pinion angle will change too much. From what I have read, the upper links length should be 70% of the lowers, 16 to 17 inches in my case.
Cutting into the floor pan for clearance and attaching my existing upper links to the frame rails was the way to go. A sleeve was needed to prevent the frame rails from crushing when the attaching bolts were tightened.
Here are some pics of the sleeves and the new upper link mount. I cut the floor behind the seat for link swing clearance. I'll enclose it when I do the tunnel work.
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11/15/2015
That was the original setup for my 24 valve wagon. After driving it for the past two months, I noticed that the left rear would bottom out when hitting a hard bump. The right side was not as bad but it still did hit the bump stops on occasion. The left side spring perch is not directly under the upper mount which is a major contributor. Relocating the perch and changing out the springs could solve this but, in need of a Winter project, I decided to go with a full coilover install.
This project will be documented in this article. 
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