Suspension Q&As

MG YB LH Front Hub Nut

Question:-

My ’53 YB1184 seems to have a rather strange hub nut as neither the Octagon Club nor NTG can put their hands on one. The car has never been “messed” with and in all respects appears to be quite original.

The story is that my existing front n/s hub nut ( that has been off once or twice in my ownership for brake linings checking etc. ) had developed a split, so thinking it would be straightforward to obtain another, I had it welded as a stop gap. This made things worse as the heat damaged the thread, so will not tighten up as it should.

My quest to find another has hit stony ground as it is not 5/8 inch BSF or UNF. The stub axle looks to be left threaded at about 14 TPI as per my re-threading tool, which looks to be more coarse than UNF.

Just wondered what you might do in my circumstances ?

Answer;-

If the car is a 1953 model, normally the thread would be a UNF (ANC) one. According to my YB spare parts book, the nuts are ” Nut, RH thread, steering knuckle, RH part number MG874/101 ” and ” Nut LH thread, steering knuckle. LH part number MG874/102 “. You could try contacting Moss or the Oct CC with the part numbers? Otherwise you need to buy a thread gauge to determine the thread.

Just in case someone has managed to fit king pins from a YA/YT, which will have a BSF thread on the stub-axle, the YA/YT part numbers are “RH thread MG890/113″ and ” LH thread MG890/114″. In theory the nuts are the same on the YB as the TD and TF.

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What tyres for a YB

QUESTION:-

Advice please. The radial 165 x 15 tyres on my YB are 18 years old and done about 12,000 miles and now starting to show minor signs of perishing. My MoT tester is OK with them to date. However, I want to have a project this coming winter to have the wheels stove enamelled and new tyres fitted. My local tyre bay says that the tyres currently on would be better replaced with crossplies for the look / originality and the fact he says that there is no advantage for a YB to run on radials other than they are more available and cheaper than crossplies. If you advise that crossplies fit the bill as a better replacement for us Y type owners albeit more costly, I will seek a supplier of 5.50 x 15 crossplies and bite the bullet ! Also the current 165 wide radials are too fat to fit into the wheel compartment of the car.

ANSWER:-

The Y was never designed for radials, and they make the steering very heavy indeed. I use 5.60 by 15, cross-ply (Camac) from Vintage Tyres at Beaulieu; 01590 612261, < sales@vintagetyres.com >. The last ones cost me £87 each and I get about 8 to 9,000 miles (4 years worth).

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Front Suspension Bushes

QUESTION;-

When I was greasing all the front suspension/steering last week I noticed that the rubber bushes fitted in the chassis end of the lower swinging arms/spring pan assembly are looking a little shabby i.e. the bit I can see is distorted and one end has a small split in it so I feel they should be replaced.

 

For a comparison between rubber and poly bushes read this article https://www.suspension.com/blog/rubber-v-polyurethane-suspension-bushings

 

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QUESTION:-

Front Springs

Question:-

I’m restoring YA0790 in Perth Western Australia.

The front RHS spring is the worse for wear, I will replace both and I have the specification for the standard spring but wondered what alternatives there are – suppliers are few and far between here. Am I correct in saying that the TD/TF and possibly MGA springs will fit and maybe even MGB? I would be happy with a stiffer spring (and ride) and I will ultimately

fit an anti-roll bar – have you any experience/recommendations for what springs to use?

ANSWER

When I renewed my front springs in 1995, I could only get MGB ones, which fitted easily! They came from NTG. You can use any of those you mention, they all fit, you will just get a 1/2″ difference in ride-height (ie lower). Often you find the lowest coil has actually broken away but is ‘hidden’ in the spring-pan. Check this pan for cracks around the bolt holes and for thinning due to corrosion where the spring sits.

 

 

Question;- I think I’ve broken a front spring on my YB, do TD ones fit?

Answer;- I used MGB ones, they are easy to fit but 1/2″ shorter (drops the front of the car about an inch) and they are cheaper than some others I could mention. Yes, TD ones fit as well. Its easy to get them out, but lining up the bolts holes on the spring pan can be fun when fitting!

YA and YB springs are identical.

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QUESTION;-

Suspension comparability
Please could you tell me if the y type front suspension, king pins and steering arms are interchangeable with a td/TF.

FURTHER QUESTION;-
Dear Neil, thanks for the quick reply and info. The parts I am really concerned about is the stub axles and the the steering arms that fit through the stub axles that the track rod ends attach to. Are they the same YB to TD?
ANSWER;-
The Y front suspension/steering is identical to the TD/TF except for the spring itself. Some bits from the MGA and MGB will also fit (see part numbers in your spares manual). YB/TD/TF use a different lever-arm damper to the YA (though both fit either car). Best place to get bits is the MG Octagon CC.

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QUESTION;-
Front shock absorbers 
I’ve recently inherited from my late grandfather a project he always intended to build, but alas it never happened and I’ve decided to have a go at it myself (I must be crazy!) he car is a special based on a YB chassis and his own body – all he had
was various bits: the chassis frame, a banjo axle, a 1500 engine and gearbox (which I think came from a MG Magnette) – a collection rusty parts really, all with the intention of building something for doing some sprints/hillclimbs – he only had the chassis frame with no log book, so I guess from a cost point of view just using it for sprints/hillclimbs made sense.I’m trying to build up a rolling chassis as the first milestone, however there is no front suspension at all. Because I’m not building an original YB, I want to build the best front suspension of the period – I know the cheapest and easiest thing to do would be to just put on some MGB front suspension, but it’s 60’s stuff and I really want to keep things from the 1950s, meaning I’m looking at YB, TD, TF and MGA front suspension – definitely the shock absorbers and uprights (I will concede
to an MGB anti roll bar and lower wishbones though). I’ve devoured all your online articles about the Y front suspension, the improvements, the similarities with TD, TF and MGA and it’s been hugelyhelpful – thank you for writing them. I’ve got a couple of questions I’d like to ask if you don’t mind at all answering them – I’d massively appreciate it as I don’t know anyone who knows about Y front suspension in as much detail as you do! Firstly, the YB, TD, TF, and MGA all seem to have an ever changing/improving front shock absorber – I am right in saying there are 4 different shapes of shock – is it just the shock body that’s changing or are the arms of the shock different too? If the shock arms are the same length/angles, are the shocks interchangeable with each other i.e. will they all work on all YB/TD/TF/MGA uprights without mucking up
the geometry?

 

ANSWER;-

Yes, there are four different ‘dampers’ fitted to these cars with the Nuffield ifs. The geometry is the same on them all BUT the MGA one has a different set of arms due to the top trunion being different. They all fit the same four bolt-holes. If you use an MGA/MGB one you will need an MGA/MGB king-pin compete.

The YB,TD,TF use a threaded king-pin, the MGA/MGB uses a plain one and a rubber top trunion (** I got the MGA wrong here, see corrections below**). The wheel hubs of the YB,TD,TF are the same as is the stub axle BUT the MGA uses a BMC wheel hub so the stub axle is different. Basically, you either use ALL YB,TD,TF OR all MGA,MGB systems; only the lower wishbone bits are interchangeable.

Neil.

Something else I missed was that the MGA and MGB use standard BMC 4-stud wheels when of the pressed-steel type; the YB,TD and TF use 5 stud wheels. This makes the wheel hubs different. This gives us four types of Y Type suspension; YA (no anti-roll bar and high lower wishbone, different 5 stud wheel centres); YB TD TF with the lower roll-centre lower wishbone and wider 5 stud wheel centres; the MGA on its own with four stud wheels and a kingpin for a disc brake caliper; MGB with plain king pin and four stud wheels. Photo is MGA.

 

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