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Front wheel bearings

Johnthesparky

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Hello,

I am rebuilding the front struts on my Astravan. so thought I’d swap the front wheel bearings whilst in there.

i believe there are small and large struts, and as I have the low blow GM diesel, I should have the small ones.

was going to have a measure, but just wondered what the different sizes were to check before ordering.

I had a look on eBay, because getting stuff is hard and that seems to be as easy as anywhere...

but one ad said 74x39x39 is the size for x17dt

Another said 72x39x37

Are these the right sizes?
And is the difference just 2mm between the small and big bearings? (If so I’m not really going to be able to do a quick check to confirm without stripping it out I guess)

the van is was built in 1996, and is a x17dt base spec van without power steering

thanks
John
 
Or a 66x34x37 which some places say is for petrols, others for my diesel too.

I could probably measure difference between the 66 and 72/74 in situ.

but confused by the difference between the 72 and 74

Thanks
 
The small block struts use the 66x34x37 bearings

The big block 1.8/2.0 engines use the 72x39x37 or 74x39x39 bearing, difference being early and late I think.
 
Re. Mk3 Astra front leg bearings. The following is my experience and deductions. I'm happy to be corrected.

The following refers to so-called 'small block' only.

I've owned my '95 X17DTL (low blow 1.7 Mk3 Astra) from new. Over the years that I've owned it, I've bought several front legs from various breakers yards. My Astra being the 'low blow', I've only bought so-called 'small block' (used) legs, originating from a variety of Astra engine/model types. I have measured the front bearing dimensions of the small block legs that I've bought, and have found at least four variants of bearing dimensions.

So I can only assume that either (a) on the car assembly production lines (different countries according to car model/year/engine or gearbox type) Astras were fitted with legs of specific bearing dimension type according to engine. Or (b) on the car production lines, legs of any bearing dimension were fitted, depending on what legs GM could source at the time of assembly.

My conclusion is this.The only way to be sure of the size of bearings fitted to any leg, is to physically measure the bearing before buying a replacement.
 
Thanks, I may have this wrong.. so please correct me if needed

A bit more reading suggests that I have small block legs too, as I have 22 splines outer CVs

Big block legs (which I believe are GSi, bigger petrol and Isuzu diesel) have 28 spline outer CVs

I’ve measured bearings this morning, but leg is loosely fitted (and verniers are up the farm, so had to use some plastic ones (better than a tape or rule though)
and I seem to have 74od and 39id bearings, but from the comments I couldn’t order bearings without checking forst

B1147C95-0AEC-494F-8480-48220A44C1DD.jpeg31E0C416-9AED-4AC5-AEE2-D9FC626D300D.jpeg72CCEE50-B3CF-48EF-9F77-79012CFB812E.jpeg

Thanks
 
>> Johnthesparky wrote >> I seem to have 74od and 39id bearings.

Those dimensions tally with GM defunct part # 90425658, superseded by GM # 90510542. (FYI, data states application for vehicles 1996 on, for chassis numbers starting with a 'T'). There does seem to be plenty of aftermarket brands available of that bearing.
 

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