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MG MGB Technical - Lower swivel torque setting

I've replaced the A arm bushes with V8 bushes. The WM does not give the torque setting; could someone advise please. The reason I ask is that when I pulled the nut up fairly loosely the castellated nut was nowhere near the split pin hole. The other thing is the WM says to fully tighten the swivel nuts before installing the spring. Is this correct; I thought the suspension nuts should not be tightened until the car is on its wheels.
Rod Merrall

Just about everything in that area seems to have a torque value except that for some reason, so 'standard' for the size of the thread. I don't know the size offhand, but it would be be 30 ft lb for 3/8", 55 for 7/16 and 66 for 1/2". That's thread size, not spanner/socket size.

The WSM would be talking about RB bushes which are of a different construction, but the V8 supplement doesn't have a section covering that. V8 pivot nuts should not be tightened until the weight of the car is on its wheels.
paulh4

Thanks for the advice Paul
Rod Merrall

I thought you squashed the rubber until either the washer hit the shoulder on the shaft or your starting compressing the insert if you have one. I must admit, I tightened the nuts with the wheel dangling. Surely the bushes will be centred better with no load on them. Now all the rubbers appear to be squashed the same amount with the lower arms in the middle.
Paul Hollingworth

I don't think you'll squash the insert, it's a distance tube. As far as the rubber goes I'd expect it to keep squashing until you hit the distance tube, then the torque will rise rapidly.
paulh4

Rod-
Make sure that some emery cloth is used in order to clean-up the pivot shafts of the lower suspension arms prior to attempting to install the lower suspension arms along with their new bushings. Should replacement be necessary, note that the pivot shafts (BMC Part # AAH 4003) of the lower suspension arms that bolt onto cross member are symmetrical and thus are not 'handed'. In other words, there is no left-side variant or right-side variant, and no front or rear to them. These must be secured to the front crossmember by means of the use of SAE Grade 5 3/8"-24 UNF X 11/4"-long machine-quality shouldered machine bolts, along with their hardened-steel flat machine washers and stiff machine nuts as well. This is another place where hardware store quality fasteners have no right to be. Good, hardened machine washers that are commonly employed in tooling can be sourced from machine shop supply vendors, normally being referred to as 'Case Hardened Finished Washers'. They should be 1/8" to 3/16" thick.
Use a flap sander in order to clean-up and polish the interior of the mounting bosses for the suspension arm bushings. This will allow the rubber suspension arm bushings to rotate freely and keep them from galling and 'winding up', either of which will quickly ruin them. Do the same in the case of the interior of the suspension arms. Any crud on these parts will play a major role in tearing up your nice, new suspension arm bushings. Once their mounting surfaces are nice and slick, do not install the suspension arm bushings in a dry state. Instead, purchase some of that wonderful silicone grease from a Honda dealer, and then spread it all over the sides of the suspension arm bushings. If you do not have a Honda dealership within a reasonable distance, then instead lubricate them by means of the use of either Lubriplate® No. 105 white lithium grease or a liquid soap solution prior to fitting. The suspension arm bushings should then slide right in. Place the suspension arm bushing and wishbone lever arm in a vice and close the jaws until the suspension arm bushing is about 3/4 of the way through the suspension arm. Next, place a large socket between the jaw of the vice and the suspension arm, and then continue to squeeze until there is an equal amount of rubber sticking out of both sides of the suspension arm.

Prior to assembly, the threads should be carefully cleaned with a solvent such as cheap carburetor cleaner and an old, soft nylon toothbrush. Be sure to apply a thin coating of heat-resistant Loctite® Marine Grade anti-seize compound onto 1/3 of the circumference of all of the threads as well as onto the distance tubes prior to re-assembling everything.

It is critical to ensure that the distance tube and the holes of the lower suspension arms are locked together. Otherwise, movement between the distance tube and the lower suspension arms will cause ovaling of the holes of the lower suspension arms fairly quickly. This is the same reason for ensuring that the bottom trunion is well-greased and that its seals are in good condition. If the trunion dries out, or if corrosion occurs, this will freeze the distance tube in place upon its mounting bolt, causing the inner edges of the holes of the lower suspension arms to turn against it, inducing premature wear.

With the exception of the body mounts of the pivot shafts, do not completely tighten anything until the suspension system is back at its fully-loaded riding height. All of the machine bolts of the suspension arms should remain loose until the car is back on all four of its wheels and has been 'bounced' up and down a few times in order to 'settle' the suspension system. Have someone sit in the driver’s seat in order to realistically load the suspension system before you crawl underneath the car in order to tighten up all of the machine bolts by means of the use of a torque wrench. If the machine bolts are tightened before the car is weighted, then the suspension bushings should be expected to wear out very quickly due to excessive preloading. Note that the spring mounting bushings should be rigidly clamped between the outer washer and the flange on the pivot shafts. The spring mounting bushing will not function correctly if it rotates.

The proper torque value settings for the front suspension system are as follows-

• Suspension arm to spring pan machine bolts: 22 Ft-lbs (dry)

• Disc brake caliper mounting machine bolts: 40 Ft-lbs to 45 Ft-lbs (dry)

• Disc brake splashguards/dust covers: 19 Ft-lbs (dry)

• Disc brake rotor to hub: 40 Ft-lbs to 45 Ft-lbs (dry)

• Front crossmember to body machine nuts: 54 Ft-lbs to 56 Ft-lbs (dry)

• Front lever arm damper (shock absorber) machine bolts: 43 Ft-lbs to 45 Ft-lbs (dry)

• Front Lever arm damper (shock absorber) machine pinch-bolt: 28 Ft-lbs (dry)

• Hub machine nut, align to next hole: 40 Ft-lbs (dry)

• Lower fulcrum: 45 Ft-lbs (dry)

• Lower suspension arm machine nuts, align to
next hole

• Lower suspension arm / spring pan machine
nuts: 22 Ft-lbs (dry)

• Road wheel lug machine nuts (Bolt-on steel
wheels): 60 Ft-lbs to 65 Ft-lbs (dry)

• Stabilizer bar link machine nut: 60 Ft-lbs
(dry)

• Steering/Pitman arm machine bolts: 60 Ft-lbs
to 65 Ft-lbs (dry)

• Steering tie rod lock nuts/jam nuts): 33.5
Ft-lbs to 37.5 Ft-lbs (dry)

• Steering rack to front crossmember: 30 Ft-lbs (dry)

• Steering U-joint/Universal Joint coupling assembly machine bolt: 20 Ft-lbs to 22 Ft-lbs (dry)

• Swivel pin machine nut, align to next flat

• Upper fulcrum: 40 Ft-lbs (dry)
Stephen Strange

What a long winded writeup of disaster
So Steve ,You're saying to use the 'special' Honda lube or lithium grease to fit the V8 bushes into the arms---------------
They should be dry in the arms not lubricated
If they have to be lubed to push in the arms hairspray is it as it dries right off, the rubber isn't supposed to move around in the arm is service, or it's life will be very short
All Rod's after is how tight to do his inner and outer swivel pin nuts up to and your answer appears to be --


• Lower fulcrum: 45 Ft-lbs (dry)

• Lower suspension arm machine nuts, align to
next hole

(after what)

I'd expect that the inner nuts would need to be pulled up to something like 40/45 lb and then look for the next pin hole after that
William Revit

That's why I had previously said the inner pivot nuts seem to be the only thing in that area that doesn't have a stated torque value, hence 'standard' for that thread size. Why that should be I have no idea.
paulh4

This thread was discussed between 18/02/2020 and 23/02/2020

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