Lime Rock Thrash: The Disassembly

[304065]

This is a new thread to describe my conversion of a 1971 911E from steel trailing arms and non-adjustable spring plates to aluminum trailing arms and adjustable spring plates and polybronze suspension bushings.



I jacked the car and put stands under the torsion bar tube, and put the tires under the car for safety. Prep work consists of:

1) Remove wheels (19mm)
1a) Remove sway bar drop links and measure droop angle (11deg)
2) Remove Calipers (19mm)
3) Remove Brake Disc (slotted screws)
4) Remove parking brake cable (10mm, one cotter pin)
5) Remove CV axle (four 10mm hex bolts (modern bolts, NOT XZN or triple-square)
6) Remove brake line (7/16 SAE and a pair of vice-grips)
7) Remove lower shock mount (22mm)
8) Remove spring plate covers (17mm)
9) Remove torsion bar covers (8mm on back of cover)
10) Remove springplates from trailing (19mm?)

Well, I'll begin with a big shout-out to Dan Jacobs who convinced me to skip the engine drop and just saw the trailing arm bolts.

Dan, your advice was spot on. The hard thing was getting the nut off- I had to use a 22mm box-end wrench, extended with my jack handle, to generate the torque to break the nut loose. Once it was loose, I used a punch to drive the bolt up against the transmission. It helps to rotate the bolt as you saw through it. There isn't much room, just enough.



Once it's all the way out, you can then use a sawzall to saw through the bolt. This was the original hardware, a Kamax 10.9 bolt, I needed to use SIX sawzall blades to cut both bolts. Also, on the port side, you have to be careful of the fuel lines and the clutch cable. . .on the starboard side, watch out for the brake line (which I severed. . .DOH!)


Success!



Issues:

1) Need new spring plate eccentrics. (Thanks DAN!) The Weltmeister bar mounts using a bolt through the eccentric, have to source one.



2) Need new bolts. The 74 and later used a M14 x 1.5 x 75. The ones on the current car are 83mm long. I tried some 80s' and they fit fine. Note that even with the 83mm bolts, the bearing surface is THREADS, which is a big no-no, even for a bolt in double shear.

3) Need new brake lines. There is a good thread here on this. I got ONE beforehand, need another one, and one to replace the one I trashed.


Stay tuned, I'm expecting a big shipment of parts this week!

Total time: six hours, including a trip to the hardware store for some new blades.

[mjshira]

nice work pal, come on out to Indy and I will make you scruffys backup crew chief!

hope all is well

James

[Noel]

Looks like you will make it to Lime Rock after all. Nicely done.

[Walko]

Good to see you are attempting it with the motor and box in place.

Michael

[304065]

More progress today. While I'm waiting for the springplates and bushings to arrive by mail, I cleaned up the spring plate covers with some paint stripper and a wire cup in my grinder. Also decided to trial-fit everything.

My initial test of Chuck Moreland's monoballs left me scratching my head as to how they would fit, until I realized that the factory rubber bushings run inside a steel insert in the arm. This insert is in two pieces, pressed in from either side, and must be removed. I pried it out with a screwdriver: be careful not to break the tip off. (I broke the tip off a German Stahlwille abusing it like this, whereas my US-made Stanley did the job fine. Interpret this as you wish. . . ) Once these were out, I could see that the monoball would be a slight interference fit. Fortunately, others have come this way before (like the old joke goes. . .)

http://www.pelicanparts.com/techarticles/911_monoball/911_monoball2.htm

The rotor fits fine, as does the caliper. The old setup on the steel arms had a flat metal strap for mounting the splash guards that fit between the caliper and the arm. The aluminum ones don't evidently require that based on the fit, the PET diagram, and the fact that there's a provision for the splash shields already on the arms. I didn't fit the pads because I didn't want to push the pistons back, but there looked like enough clearance.

Brake Lines Alloy Trailing Arm Conversion

The above thread is very helpful, it gives the correct part number for the brake line you need when doing this conversion. Which number is: 911 355 621 02. You can see it there in my trial setup.


So far, so good. Stay tuned.

[patkeefe]

John:
I picked up some new bolts when I had my SC trailing arms out. I think I bought them from our hosts. A bit longer is better, and they had enought shank to go all the way through the bushings without being on threads.

Are those old surplus houses still down on Canal Street? I remember going there in the 70's and finding all kinds of neat and weird hardware.

Pat

[Shuie]

What year are your trailing arms from?

I bought a set of '74 trailing arms under the impression that they were a direct swap for earlier steel trailing arms. Changing a brake line is not a big deal, Im just curious if I need to with the '74 arms.

TIA

[304065]

Sherman, the arms are from a 1974, with a 1973 casting date.

Interestingly, however, one of the arms has a 1988 casting date: it's a Carrera arm. . . these arms are from a wrecked car (but straight) and the PO must have damaged one of them along the way: they have one ball stud (on the 1974 arm) and one tapped insert (from the Carrera arm).

The whole point of using '74's is that the 915 gearbox in that year still used the four-bolt drive flanges, like the earlier cars. So the '74 arms will work with your existing 915 four-bolt drive flanges without modification.

You could, I believe, get a set of bare SC or Carrera arms (which have six-bolt flanges) and swap your flanges over, but I didn't want to bother with that, and plus these arms were complete. The only issue is that I will have to change the wheel bearings: there isn't much play in these but the age/condition is unknown. However, I'm going to wait until the car's back on the ground before I try to get that big nut off.

I believe you must change the brake line. In the mockup process there was no way I could make the existing line fit.

Pat, I think those surplus houses have probably been converted into multi-milion dollar urban hipster loft apartments. I'll check next time I'm down on Canal Street picking up a fake rolex and some bootleg DVDs

[Walko]

John,

I would be getting a loacl mechanic to undo the nuts whilst it is all apart. an dthen it won't be to hard to have the new bearing pressed in before re assembly

My two cents worth.

Michael

[patkeefe]

John:
Wheel nut...impact wrench at 80 psi, and use an 18" piece of uni-strut as a brace across the wheel studs wedged onto the floor to keep it from turning. I just went through a wheel bearing fiasco. The machine shop put new ones in, but screwed up the hole, so I had to fix it and have them redone. Then, the right side was lumpy, so I built a tool to take it out in place...there is a limit as to how many times I want to R&R the traling arms. Tool works great for removal, and heat up the aluminum arms with a propane torch to put the bearings back in. They slide right in. If you need the tool, let me know. I can put it on the NJ transit #56 from Ringwood, and be at the PA bus terminal in an hour!
Pat

[304065]

Rear Bumper- Rennspeed- Check
Trailing Arm Bolts- M14 x 1.5 x 80 Grade 8.8 -2x Check(McMaster)
Monoballs- Check (Elephant Racing)
Polybronze Bushings for SAW Bars (Elephant Racing)
Brake Line-2x Check (911 355 621 02) (SIC)
Brake Line Clip- From '71
Flex Brake Line- From '71
Spring Plates - Check (PP)
Spring Plate Bolts- M12 x 1.5 x 35 (900 083 019 08)- 4x Check (SIC)
Spring Plate Schnorr Washers- M12- (999 523 109 02) -4x Check (McMaster)
Spring Plate Hardened Washers- M12- (901 333 143 01) -4x Check (McMaster)
Spring Plate Nuts- M12 x 1.5 (N 011 020 8) Grade 8 -8x Check (McMaster)
Toe Eccentric- Weltmeister- 2x Check (Performance)
Toe Eccentric Schnorr Washer - M12 - 2x Check (as above)
Toe Eccentric Hardened Washers - M12 Missing] 2x
Toe Eccentric Nuts- These are freaking SAE, will be locally sourced. According to Weltmeister, they make everything in SAE so it will be easier to get replacement parts.
Camber Eccentric- (901 333 133 04) -2x Check (Fred Lavery)
Camber Eccentric Schnorr Washer- M12 -2x Check (as above)
Camber Eccentric Hardened Washers - M12 Missing] 2x
Camber Eccentric Nuts- M12 x1.5 (900 078 017 12)- 2x Check (as above)
Shock Mount Bolts- M14 x 1.5 x 80 (900 082 054 02) -2X Check (PP)
Shock Mount Washers - M14 (999 025 062 02) -2X Check (Pelican)
Rear Wheel Bearings - '74+ (999 053 020 01) -2x Check (Pelican)
Rear Wheel Washer - (999 025 046 01) 2x Check (Pelican)
Rear Wheel Nut - (9XX 332 806 00) 2x Check (Pelican)
Rear Wheel Cotter Pin (N-012-538-1) 2x Check (Pelican)
Parking Brake Shoes- From '71 Assembly
Parking Brake Spring- Short - (A-352 932 10) 2x Check (Pelican)
Parking Brake Spring - Long (A-352-954-10) 2x Check (Pelican)
Parking Brake Conical Spring Retaining Washer (A-352-955-10) 2x Check (Pelican)
Parking Brake Conical Spring (A-352-957-10) 2x Check (Pelican)
Parking Brake Conical Spring Retaining Pin (A-352-959-10) 2x Check (Pelican)
Parking Brake Expander (C-352-090-00) 2x Check (Pelican)
Parking Brake Adjustment Screw Bushing (C-352-944-00) 2x Check (Pelican)
Parking Brake Adjustment Screw Nut (C-352-098-00) 2x Check (SIC)
Parking Brake Expander Spring (A-352-953-10) From '71 (same part number)
Parking Brake Cables- From '71 Assembly
Parking Brake Spacer Tube- (A-424-557-01) From 71 (same part no.)
Parking Brake Castellated Nut- M10- (J-079-012-02) From '71
Parking Brake Castellated Nut Cotter Pin- hardware store
CV Joint Bolts- From '71
CV Joint Schnorr Washers M1- have a box from before
CV Joint Gaskets (A-332-297-00) have 2, 2x extra from Pelican
CV Joint Lock Plates - From '71
Caliper Bolts- From '71
Caliper Washers- From '71
Castrol SRF
Pagid Orange Pads
CV Joint Grease- Valvoline
Orange Anti-Tampering Paint (Aircraft Spruce)

[Shaun @ Tru6]

John, I'll be doing this exact job in about 2-3 weeks on my 69E. Thanks for your excellent post!

I'm using '87 complete trailing arms, and of course have a 901 in the car. Do you know if I can just use late axles and put on an early inboard CV joint? Is that possible?

Or do I have to pull out the bearings and hub from the 87 and put in new bearings and early hub, and then use my existing early axles?

[patkeefe]

Just a note:
My 78 SC has six bolt flanges and CV's. Looks like it came from the factory this way; the date stamp on the CV's was 1977.
Pat

[Shuie]

This is a great thread

John, I just bought a 3.2 Carrera motor to go into my '72. Im also shopping Carrera 915s right now. Assuming I find a nice 915 from a Carrera, which do you think would be easier:

Use the '74 alloy arms or buy a set of 3.2 trailing arms?

TIA

[304065]

Forgot to add the reassembly

Lime Rock Thrash: The Reassembly