Roadster rear axle not straight

[Dave lee]

Hi all, this is my first post so fingers crossed.
I have recently sold my roundnose Mini and am now the proud owner of a 67 Roadster. I have one issue with it (so far :) ) the rear axle isn't sitting straight, there's about an inch difference on the front wheel arch gap, I've had a look and no sign of a broken spring, shackles and bushes are fine as are the mountings, I am wondering if a spring has been replaced with a pattern one, does anyone know the measurements of the spring, centre bolt to front and rear bush centres? Thanks in advance, Dave

[Peter Cresswell]

Hi Dave
Welcome to the MGB ownership. Prior to buying my MGB, I too had a Mini (a Mk1 Cooper)!
If you can get the car onto a flat surface (in your garage would do), try taking a plumb line down from the centre of all 4 wheels (a bit fiddly if you have wire wheels!) and make a mark on the floor, then measure the length on both sides. These measurements should equal the wheelbase of the MGB which is 7ft 7in (231.1cm). If they are different on both sides, then your assumption that the axle doesn't sit square in the car is right, and then check for damage to the rear chassis rails. If they are the same and equal to the wheelbase, then all is ok and probably the reason is due to some restoration work around the front of the inner wheel arch, which is necessary if the sill structure has been replaced.
Other things to check are does the car sit level when at standstill with no occupants in it, which it should do. Whilst you have the tape measure out you can also check that the ride height is the same on both sides by measuring from the bottom of the chrome strip to the centre of the wheel. Unfortunately it is difficult to establish a 'standard' measurement for the ride height as many thing conspire against that (replacement panels, spring age and manufacturer, even chrome line alignment), so just check they are about the same on both sides. On my car they were within 1/2 in between both sides at the rear and at the front. This is probably as close as you can get!
One other thought is to check the rubber (or poly) pads are in place above and below the spring (item 19 in the attached picture) and by looking from directly below the plate that the shock absorber attaches to (item 20) that the bush (item 5) is present. Without the pads and the bush there is ample scope for the axle to move. Also check the U bolts are tight.
I can't find details about the spring dimensions (length, bow etc) other than they 1.75in wide! There used to be an internet site that contained then but that seems to have disappeared! If I find it I'll post it here.
Good luck

[Dave lee]

Hi Peter, thank you for your quick reply, I jacked her up on my drive yesterday but it was quite hard to get a good measurement of both springs to compare. All bushes and U bolts etc are good as is the chassis, I noticed two things though, it has a new (or new ish) off side spring and the shackle is angled further back under load compared to the older one, plus signs of the spring eye hitting the chassis, and on level ground she sits a lot higher off side to! I am wondering if it is a bad pattern part spring causing my problem, if so where do you recommend getting a good matching pair from?
Thanks, Dave.

[Peter Cresswell]

Hi Dave
It sounds as if someone has replaced just one spring, which is never a good idea. I would tend to buy from one of the major suppliers, but one you can talk to first to explain your problem and hopefully they can put the springs side by side before they ship them to you. So some contacts for you:
MGB Hive - 01945 700500
Brown & Gammons - 01462 490049
I have bought from both of these and had good service and advice over the phone.
Don't forget to check sure if the springs are supplied with the front bush, and MG RV8 rear shackle bushes will tighten things up a bit without the harshness of polybushes.

A word of warning though - the new springs will cause the car to sit high, as they will settle with use over time. The problem is any classic car now will not do the mileage for the springs to settle, so you will see many MGBs running around with a distinct tail up, nose down attitude. You can correct this by using a lowering block between the spring and the axle, and if the springs do settle enough, take them out later on. How much it does this of course is also affected by the front ride height and springs!
If you can get to the MG and Triumph Show at Stoneleigh on the 21st Feb., you will save the P&P with Brown & Gammons (might cost more in fuel from Leigh on Sea than the postage though!!).

Spring settings and ride heights are a real minefield on the MGB.

[Peter Cresswell]

Hi Dave,
Found it! This is the article I was referring to in my first reply to you. It is very practical stuff with lots of good tips, but the rear suspension is quite a way down this long article.
http://www.mgb-stuff.org.uk/suspensiontext.htm
there are lots of articles here, so if you want the whole range, go to
http://www.mgb-stuff.org.uk
and click on 'Spanners' in the black box on the left. Lots of good info!

[Dave lee]

Great info Pete, I'll ring hive in the week, I have just fitted a replacement breather diaphragm which I got from them.