Wheel and beam bearings - replace or reuse?

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Evil_Fiz
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Wheel and beam bearings - replace or reuse?

Post by Evil_Fiz » Sun Jan 15, 2017 4:20 pm

The car in question is a 1970 Convertible Karmann Ghia. The car sat well protected in a barn since 1993 until I squired it in 9-15. The front brakes appear to have been replaced shortly before it was parked. The beam looks original as does the rear end.

The safe answer is replace everything so here is my dilemma:
- The engineer bound for the nervous hospital in me says replace all the bearings and bushings.
- The resource conservative, reuse-recycle, hippy tree huger in me says reuse the parts if they are viable.
I am going to spend a fair amount in my restoration so the $$$ has been allotted, I just don't want to waste money on replacing parts that don't need it nor do i want to create create unnecessary waste.

If the wheel and beam bearings, and metal beam bushings can be reused, how do I test them for structural integrity and wear?

Thanks,
Emil

Ol'fogasaurus
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Re: Wheel and beam bearings - replace or reuse?

Post by Ol'fogasaurus » Sun Jan 15, 2017 4:30 pm

I would remove the bearings, clean them then lightly put them in the races and turn them around by hand (fingers in the spindle holle) feeling for any humps and bumps. Don't get too much pressure on them as you don't want them or the races scored. If OK the repack and replace the seal. If you feel anything but smoothness then you might want to replace the bearings and races in question.
Lee

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Marc
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Re: Wheel and beam bearings - replace or reuse?

Post by Marc » Sun Jan 15, 2017 5:08 pm

The outer needle bearings in the beam (111 401 301 upper, 311 401 301C lower - ~$20 ea) are designed for one-time installation (the outer lip is significantly thicker than the inner one; that makes it difficult to remove them without damage). The inner bushings on kingpin beams were one-piece Micarta; balljoint bushings are a two-piece affair with an inner metal sleeve - hard to find but still around (131 401 313)
The pragmatic "solution" is the one-piece tubular urethane bushings popular for off-road use, but IMO that's the only place you'd want to use them. They typically start out too tight and then develop slop with age, and they squeak!
The condition of the inner bushings can usually be assessed pretty well by close inspection of the control arms - if they still look pristine the bushings should be fine as well. Same goes for the outer bearings, plus those can be inspected in place without a borescope.
Remove the torsion bar stacks and insert the control arms; wriggle them and observe how much movement is present at the balljoint (it should be barely perceptible).
If the OEM shock absorbers with snubbers have been replaced with generic style there's more reason to be concerned about the condition of the upper/inner bushings - if the suspension should bottom out to the limit of the balljoint travel they take the worst of the shock.
New Brazilian-made beams are available but I'd rather have a used German one if it's straight and the bushings/bearings are still serviceable.

Wheel bearings can be checked as Lee described - also inspect the spindle journals, particularly the outer ones, for wear (new diameter is 17.45-17.46mm; if there's a step big enough to catch with your fingernail the spindle should be replaced). Grease seals for 68½-up disc brakes are 311 405 641B; Rabbit rear seals (321 501 641) also work and may be somewhat cheaper.

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gtmdriver
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Re: Wheel and beam bearings - replace or reuse?

Post by gtmdriver » Mon Jan 16, 2017 5:26 am

Wheel bearings are cheap so I replace them as a matter of course.

I have just replaced the front beam bushes on my ball joint Type 1 beam.

It is not an easy job.

The only way I could find to drift out the bushes and bearings is to remove the trailing arms and the spring leaves then use a long drift made from 12mm (12") steel bar to drift them out from the opposite side of the beam.

Cleaning out the beam is ok but messy as it will probably be full of old grease all the way through.

Heritage supply two types of replacement inner bush. The 'OEM' type is now a one piece composite fibre bush which is an incredibly tight fit in the torsion tube and needs reaming to size once fitted. I had to make up my own reaming tool to do this. The alternative that they supply is a one piece Teflon or nylatron bush which supposedly does not need reaming. I have no experience of this as I chose the OEM version.

The outer bearings drift in quite easily so long as you have a suitably large drift (socket) to apply even force all round the outer casing. The dust seals just push in.

Check the bearing surfaces of the trailing arms as they wear at the inner end forming grooves. While you have them out you should also check the ball joints as this would be a good time to replace them if necessary.

At this stage it may be more cost effective to fit an entire replacement front beam.

Do not be tempted to fit the alternative polyurethane bushes. They flex under braking allowing the trailing arms to move backwards and destroy your toe settings. Eventually cold flow sets in and the distortion becomes permanent. Mine were in for about 2000 miles before I refitted the OEM bushes and bearings as described above.

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Re: Wheel and beam bearings - replace or reuse?

Post by Ol'fogasaurus » Mon Jan 16, 2017 11:03 am

I had been told of using a long rod to drive the old bearings out but someone, either Dusty or Marc (I think), told me of another way of doing it. By memory (I did a search but couldn't find the post) you can make a tool out of a thick washer that is attached to a rod or slide hammer. The washer has to be the same or very close to the inner diameter of the beam. Two opposing edges have to be ground to the inner dia. of the bearing so that it will allow the washer to slide through the bearing then be allowed to edges of the washer to hook onto the inner surface of the roller bearing. connecting the washer to the pulling device has to be figured out as I don't remember to be honest but it wasn't hard to do.

The rod/slide hammer is then put in to action pulling the bearing out of the tube. If there are two bearing per arm then you have twice the fun of removing them from each side.

Have fun making the tool if you want to go this way.
Lee

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Evil_Fiz
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Re: Wheel and beam bearings - replace or reuse?

Post by Evil_Fiz » Mon Jan 16, 2017 2:21 pm

If I understand you correctly the washer needs to be shaped something like this, (_o_), and then it gets used in a fashion similar to a toggle bolt. If so, how would it tilt to slide through the bearing hole? I envision a slotted hole in the center of the washer. Thanks for the ideas, I will need to ponder this a bit.

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Marc
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Re: Wheel and beam bearings - replace or reuse?

Post by Marc » Mon Jan 16, 2017 4:53 pm

I suppose you could get fancier if you wanted to, but I've always gotten away with just a simple thick washer with opposite sides ground flat and a round center hole large enough to introduce a hooked-end slidehammer tool, and rotating it a little between blows.

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Re: Wheel and beam bearings - replace or reuse?

Post by Ol'fogasaurus » Mon Jan 16, 2017 7:29 pm

^^^^^ what he said! ^^^^^^^
Lee

My opinion is worth slightly less than what you paid for it.

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