Longevity of front tie bars

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jagnut66
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Longevity of front tie bars

Postby jagnut66 » Sun Oct 20, 2019 1:09 pm

Hi,
I am in the process of going through my suspension, front and rear, refurbishing it / replacing all the bushes. Another club member has raised the issue of the longevity of the front tie bars, stating that they should ideally be replaced every couple of years, as they can fail, with rather nasty consequences.
I have never heard of this before and, unless they proved to be excessively worn / rusty, was planning to just refurbish them and replace the bushes.
Is what he says correct and, as they are probably much older than the above, should I be looking at replacing them?
Many thanks in advance for any advice and your opinions / experience with this.
Best wishes,
Mike.
1954 Series 2 on axle stands needing more welding......

ManyMinors
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Re: Longevity of front tie bars

Postby ManyMinors » Sun Oct 20, 2019 1:52 pm

I have never had to replace a tiebar on any of my own Minors! I do know that they can wear at the front if the bushes become worn and the tiebar effectively becomes slack, so they should be checked from time to time. When the bushes are badly worn, the metal tiebar rubs against the chassis mounting bracket. I know of no other weakness.

ianmack
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Re: Longevity of front tie bars

Postby ianmack » Sun Oct 20, 2019 2:24 pm

Does he mean replace the bars or just the bushes? My Minors have all had old bars, probably original and I’ve never known one to break. I have seen one or two which had worn narrow where the front end had moved against the bracket but this shouldn’t happen with good bushes.

Personally I would regard these as visual inspection replacements, new bushes when they become perished or misshapen and then examine the bars. Two years seems a bit excessive for the rubber bushes and completely unnecessary for the bars.

jagnut66
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Re: Longevity of front tie bars

Postby jagnut66 » Sun Oct 20, 2019 3:29 pm

Thanks, this was my original thinking on the matter.
Of course if there is wear / a thinning of the bar, then I would automatically replace them.
Best wishes,
Mike.
1954 Series 2 on axle stands needing more welding......

SteveClem
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Re: Longevity of front tie bars

Postby SteveClem » Sun Oct 20, 2019 6:43 pm

In my experience,they seem to last forever. But the cars are kept indoors.

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Sun Oct 20, 2019 8:34 pm

One thing that does happen with the tie bar is that the shoulder of the tie bar that the rear bush retaining washer sits against can (and especially if the bushes are worn) round off and the washer can slip over the shoulder. Whilst not as serious as the front washer giving way it can still upset the steering/handling. When the bushes are replaced the tie bars should be examined to ensure that it has a good square shoulder and that the washers are a good fit on the tie bar and the washers have not been distorted with use.

The original BMC rubber bushes were next to useless and regularly had to be replaced. If not kept an eye on - the bushes fell to pieces and then the tie bar rattled against the tie bar chassis leg bracket.
I always recommend that the bushes are replaced with a poly bush to the front for braking resistance and a modern rubber bush to the rear for articulation.


don58van
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Re: Longevity of front tie bars

Postby don58van » Thu Oct 24, 2019 2:27 am

I have just bought some new poly bushes for the tie bars on my Minor.

I have a durometer (a fairly low cost one--the absolute values are of uncertain accuracy but it gives consistent results) so I thought it would be interesting to see how the hardness of my new poly bushes compare with some rubber ones I have to hand.

SuperPro poly*: 84 HA
ESM new rubber (bought several years ago): 67 HA
MOWOG used (1970 vintage): 73 HA

The numbers might be meaningless to many, so I would say that in practical terms, when I give them a squeeze with my fingers, I can feel a difference between all three. The ESM ones are noticeably more squishy than the SuperPro poly ones.

Note: The poly bushes have a slightly smaller diameter than the rubber bushes I tested, so in service, they might be relatively more compressible than the above figures suggest.

* Part number SPF2755SK

FYI
Don

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Thu Oct 24, 2019 10:05 am

The higher the number the harder the rubber/poly.

https://www.ebay.co.uk/itm/Morris-Minor ... SwihJZ3sGu


jagnut66
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Re: Longevity of front tie bars

Postby jagnut66 » Thu Oct 24, 2019 11:32 am

I always fit the green ones, I don't think they are the hardest but then that is probably for the best, as a little give is probably better on a Morris (depending on what you are going to use it for, of course).
Best wishes,
Mike.
1954 Series 2 on axle stands needing more welding......

jaekl
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Re: Longevity of front tie bars

Postby jaekl » Thu Oct 24, 2019 11:52 am

The poly bushings need to be smaller because they are really not bushing like the rubber ones but actually bearings. The rubber squirm and must be compressed to ensure no rotation. The pin does rotate in a poly bushing, so silicone grease is required.

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Thu Oct 24, 2019 12:18 pm

For the tie bar application the bush does not need to be smaller as the forces acting on the bush are not rotational but fore and aft with some vertical forces as the suspension goes up and down.

By all means lubricate the bushes when fitting but I would use red rubber grease as I have found that silicon grease soon washes off.

One of the advantages of the poly bushes shown in the link is that they have got the raised center that fits through the tie bar chassis bracket so stopping contact between tie bar and chassis bracket. The original BMC bushes had the raised centre but many after market bushes now supplied do not so you need to squash the bush sufficiently to discourage contact between bar and bracket.


Edward1949
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Re: Longevity of front tie bars

Postby Edward1949 » Thu Oct 24, 2019 3:24 pm

My tie-bar story: nearly 50 years ago I bought a late 1950's Riley 1.5 (that's the one based on Minor chassis) with front-end shunt damage, dirt cheap but still driveable, bought it to use till MOT expired then scrap it. I used it heavily for some months (regular long fast motorway trips with that lovely 3.73 diff) but always noticed a front-end rubbing noise on the rare occasions of heavy braking. Brake pads looked fine, but then noticed highly polished rubbing marks on trailing edge of n/s front mudguard - the front tyre was obviously contacting the mudguard under heavy braking. On visual inspection the tie bar looked perfect. Only when levered did it reveal a complete clean break at the front bracket end, presumably related to the front-end shunt. The odd thing was that the handling wasn't noticeably bad for a high mileage car in those days. The front wheel must have remained in its correct location except under braking but I dread to think of the forces on the inner attachment point of the front suspension arm :o

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Thu Oct 24, 2019 7:38 pm

The problems with the tie rod bushes was one of the main reasons I fitted a rose joint to the front of the tie rod.

Good for a track car but not recommended for a road car.
Minor adjustable tie rod 1..jpg
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don58van
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Re: Longevity of front tie bars

Postby don58van » Fri Oct 25, 2019 8:57 am

Just to add to the lubricate or not to lubricate discussion...
SuperPro provided lubricant with my eyebolt bushes, but not with my tie-bar bushes.

This supports PTH's view (above) that the tie-bar bushes are a special case because there are no rotational forces/movements.

Don

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Fri Oct 25, 2019 9:15 am

The eye bolts on my Minor fitted with poly bushes have had grease nipples added so that bushes can be lubricated to ensure that rotational loading is kept to the minimum.
100_2131.JPG
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Sleeper
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Re: Longevity of front tie bars

Postby Sleeper » Fri Oct 25, 2019 9:51 am

Is there any part of your car that could be considered " slightly grubby " ?

John :wink:

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Fri Oct 25, 2019 12:40 pm

Only the driver :D

This is the grubbiest part of the car and it will be made near spotless in due course as I undertake several upgrades and revisions to the rear suspension.
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dudload
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Re: Longevity of front tie bars

Postby dudload » Fri Oct 25, 2019 3:15 pm

Silly question and more borne out of wondering than Having tried to do it yet, but how are you meant to undo the nut at the chassis side of the tie bar? Always thought it looked and extremely tight fit, or do you undo the other side first and then rotate?

philthehill
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Re: Longevity of front tie bars

Postby philthehill » Fri Oct 25, 2019 4:33 pm

You can do either.

As regards the split pin through the castellated nut I would not try to remove it whilst the bar is in situ - just put a spanner on the nut and undo - remove the remains of the split pin when the tie bar is removed from the vehicle. The split pin is so thin it will not damage the tie bar or tie bar nut.

To rotate the tie bar you have to remove the location bolt/nut at the lower suspension arm end. To rotate the tie bar insert a cross head screw driver of 5/16" O.D. through the tie bar hole which can be used to either hold or rotate the tie bar.

Removing the nut and bolt at the rear of the tie bar allows you to push the tie bar towards the chassis leg which gives more room for a spanner to be fitted over the castellated nut at the front of the tie bar.

I always replace the castellated nut with a self locking nylock nut.


dudload
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Re: Longevity of front tie bars

Postby dudload » Thu Oct 31, 2019 3:20 pm

thanks! idiotic question, but what size of nylock nut should I be purchasing? can't find the thread anywhere..

EDIT - didn't search hard enough. found the 7/16" UNF on ESM!


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