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MG MGB Technical - Replacing Leaf Springs

Okay, I almost went on Ebay and started bidding on a pair of new 6 leaf springs for my 72B, but somehow I got diverted and I wound up talking to my neighbor first.

I mentioned 2 things, for which I am seeking additional feedback. First - for reference I do not have that air foil that mounts below the front bumper, if that matters in any of this.

#1
I mentioned that it is odd, that when I drive up around 70 mph the front end feels like it is floating. I recognize the feel from when I piled my trunk full of sidewalk pavers until the rear end bottomed out and I slowly drove home with very little feel in the steering.

This prompted neighbor to comment that when I drive by, the front end of my B is raised. Others have commented that my B rides too low. I've checked specs and I'd agree the rear fender arc is down an inch or more too far when compared to tire, even without my 250 lbs in the car.

This all points to the need for new leaf springs.

Which leads me to the questions...

1. Should I purchase Moss or VB or LBC 6 leaf springs, in the hopes new springs will cure all,
or
2. Should I purchase 7 leaf springs, (for GT), to give a bit more resistence for my 250lbs,
or
3. Should I consider heading to a spring shop in the Metro here, and ask them to either re-torque my springs and firm them up a bit extra,
or
4. Should I head to spring shop and have them build a set of springs for car that meets my larger bulk?

Your thoughts please.

P.S. Anyone following my other trials & tribulations should be updated that I now have my heater box out of the car, after getting vent control cable release from control, it only took a crowbar to break the box loose from the firewall... Yes, all the gaskets & seals were rotted and things got a bit rusted to firewall. But its out and I've order loads of parts to rebuild it. Ahh, progress!

Thanks.

BobA
R.W Anderson

Bob-
You can have your rear leaf springs re-arched, but they will sag again before long. You can also have your rear leaf springs custom-made, but the ones from Brit Tek are the closest to Original Equipment quality that you're going to find pre-made. Brit Tek has a website at: http://www.brittek.com/ Whatever you do, don't get the rear leaf springs from Victoria British unless you like having your car sit very high at the rear. No, they won't settle to correct height. Seven-leaf MGBGT rear leaf springs on a Roadster will give a very stiff ride.
Steve S.

Bob-
Hunt around for a good spring shop that can build you a set of springs. Steve is right, I had the same problem with VB springs. Last summer I broke a spring on a trip and was lucky to find a local shop who made me a new main leaf. When I asked him about sping quality he stated that unless you use US or Canadian spring steel you will have problems, his openion was that the ofshore sping steel was of poor quality. They hand made the new main leaf for my car and were within 1/4" of matching the ride height.
John H

If I go with having springs made locally, what should I expect for a price range & what if any specs would I need to provide to a shop? Or can they pretty much figure this stuff out, as they are in the business?

Thanks.

BobA
R.W Anderson

Bob,

I know opinions differ on this, but I have used GT rear springs on my ī63 roadster for six years now, and am very happy with them. The ride may be a little stiffer, but I rather like it that way. We use our car for many long trips with lots of luggage, and neither I nor my wife are featherweight.

In Norway this is a very common modification, people just get tired of driving on the rubber bump stops when touring with luggage. I was lucky to find a pair of decent quality NOS Unipart springs with interleaving.

I also find that the slightly stiffer rear end makes the MGB more neutral through the bends, and I like that too. With 28 psi tyre pressure front and rear and polyurethane bushes everywhere the car is now very responsive, and yet very comfortable, even on long runs.

Tore

Tore

Like Tore I was fed up with bottoming and grounding when touring fully loaded, even with new OE springs, and like him I fitted uprated rear springs. However unlike Tore I didn't like the harsh and choppy ride they gave over some surfaces so I reverted to the correct type and opted to extend the rear shackles instead and am happy with the result.

One must bear in mind that MG only allowed 150lb per occupant, higher than that and you may well have to go harder. The most common complaint with rear springs is that they are too hard/and or arched, meaning that you can't get the rear shackles or rebound straps attached using just the weight of a fully equipped car without adding condiderable extra weight to the boot, and giving a very rear high stance afterwards. I've bought three sets of springs over the years from different suppliers and never had that problem, even with V8 rears which are the hardest. Front springs have been a different issue though, being noticeably taller in free height as well as ride height.

What are the distances between the centre of the hubs and the bottom of the trim strip with you out of the car and in? I would have thought you would have to go a lot higher at the front than the rear to get any kind of lifting at speeds, my fronts are an inch higher than the rears unladen now (but then I'm inside Abingdon's allowance) and I haven't noticed any handling issues, but like you I have experienced what it can feel like with a very heavily laden boot.
Paul Hunt

Anyone know where to get some good quality Spring clamps (clips) in US? preferrably mail order?
Mike
MK Mike

Bob, when I broke the main leaf on the trip above they charged me $104 to take the old spring off, make the new main leaf, and put it back together and on the car. We were so thrilled that they saved our vacation that my wife gave them a $40 tip. Having a complete set made will cost more then the VB or Moss springs but you will likely get a much better product.
John H

As I said I think I have been very lucky with my particular pair of springs being of original quality. I had no trouble at all with shackles or rebound straps.

With the quality problems that seems to be the rule now Paulīs combination of extended rear shackles and roadster springs is probably a very good solution. But I think you should then definitely use blue polyurethane shackle bushes to keep the rear suspension stable.

Tore
Tore

Listen to John H., A good local spring shop can build what you need. How it works is when you find the right shop there will be a 'guy' who will ask you the right questions and build the springs you need I've done this from the 70s with zero problems and always at a price I could live with. Local people with American raw materials,How can you beat it? RIC
RIC LLOYD

I measured my loaded and unloaded heights last night.

I measured from the center of the hub to the bottom of the trim.

Unloaded: LF = 13 1/8" LR = 13 1/2"
Loaded: LF = 12 7/16" LR = 12 7/16"

This implies the car is more level when loaded, but it also shows the rear drops more than front (11/16" drop in front & 1 1/16" drop in rear, which makes sense.

I'm not sure how this compares to specs, but a side view of my car shows the top of the rear tire well up in the wheel well.

Your thoughts please.

BobA


R.W Anderson

I was told by a spring manuf.in Detroit,Mich that you cant(very hard) get the british size steel(width) to properly make the rear springs.Comments???I was also told that a persons old springs are really not to be re-torqued. Comments Thanks,Rich
rich osterhout

I was having the same problem with bottoming out when loaded in my BGT with V6. I put on air shocks and solved the problem
My 74 BGT was sagging in thr back so yesterday I pu air shock on it also. It sure doesn't sag anymore.

Steve
Steve

The front end lifting will be eliminated with the front spoiler.

As far as the springs it depends on what you use the car for. But I would suggest Brit Tek as an earlier post staed. Also I have seen on the MG Experience forum where you can use Suzuki Samari springs as well. Here's a link for the Chicgoland MG club tech session on springs.

http://chicagolandmgclub.com/photos/leaf_springs/
S.L. LaPaugh

Thanks I've printed out the Chicago Tech session for reference. If our tech article writer is caught short some month, I'll seek permission to slip the spring tech session article in the newsletter I edit for our club.

Reading the info from Chicago Club is like watching a J. Twist Univ Motors clip on YouTube, it looks all too simple.

BobA
R.W Anderson

"yesterday I pu air shock on it also. It sure doesn't sag anymore."

Whilst harder dampers of any type will reduce bottoming at the expense of a harder ride, only if you replaced the damper *and* spring assembly i.e. leaf and lever-arm for a coil-over would you be able to change the static ride height i.e. correct sag. Changing the dampers (the air shock?) only will not affect static ride height (unless they are siezed!).
Paul Hunt

Paul,

Maybe air shocks means something else over there. Maybe what we call gas shocks you call air shocks (dampers).

Air shocks are a combination of a shock (damper) and an air spring. You pump them up with an air compressor, and they will raise the ride height. It is a common addition for heavy loads or trailer towing.

Charley
C R Huff

Air shock have a bladder that holds air. Mine are rated for 25 to 200 PSI. I run them at 30 to correct the sag. They are not any hadrer riding than the previous tube shocks and not much harder riding than the levers of years ago.
It seem to ride as well as others MG's in our club, unless I put in more than 40 to 50 psi.
With a load in the back I will increase the pressure to bring the back end up but it doesn't ride bad then because of the extra weight back there.
I did have to try several sets of shocks to find one that was valved soft enough for the B.

Steve
Steve

Fair do's, not come across them over here. Still learning.
Paul Hunt

Steve,

Given that you had to try several sets to find a good match, I think you owe it to the rest of us to share the manufacturer info and part numbers eh?

We taught Paul something? That's a pretty tough trick.

Charley
C R Huff

I ordered form Car Quest Auto Parts.
Their part number is 50845.
The number stamped on the shock is 729207.

Steve
Steve

Thanks Steve. Do you happen to know the manufacturer?

Charley
C R Huff

Charley,
I think it is Monroe.
There is no name on the shock.
Steve
Steve

Thanks again, Steve.

Charley
C R Huff

Charley,
I had already coverted both my B's to tube shocks.
I had to lower the lower shock mount by 1.5 to 2 inches to make these air shocks work. Not much trouble, but otherwise they bottom out before the suspension travels it full movement.

Steve
Steve

Steve,

I figured you had converted to tube shocks, but would not have guessed the modified location. I don't plan on doing this to mine at the moment, but at some time I intend to put a trailer hitch on the GT so I might need it then.

Charley
C R Huff

Well the leaf spring swap is complete and I still have 5 fingers on each hand and only minor cuts & scrapes.

For something that is suppose to be rather basic in auto repair, it sure required a lot of time and every jack I had in the garage.

One caution or lesson I learned was in how to manage disconnecting the link arm from the bottom bracket below the center of the leaf springs.

I found that trying to loosen the lower link arm from the bracket was impossible as the end turns in the arm. Same thing happened to attempts to remove nut from top of link arm. If there was suppose to be some trick to getting these connections loose I never found it. Instead I simply disconnected the damper box from the vehicle and let the whole assembly down to the floor, never disconnecting it from the bottom bracket beneath the leaf springs. Made for a much quicker re-install.

Results of replacing with GT springs on Roadster: I went from 13 1/2" center of hub to bottom of trim to 15" - 15 1/4". Of course when I was done, it was more like 16" - 16 1/2", but driving it around has settled things down nicely. We'll see how weeks of driving changes things, but car looks better raised up a tad, and the ride is totally different. No more boucncing sideways on bumps in turns.

Passenger side was done 1st and took 6 hours, with lots of time digging out various little jacks to support things while working. Drivers side took more like 4 hours of work. No power tools and plenty of rusted parts. Shop time estimate was 3 hours for both, so I figured 6 hours for me doing it on the ground by myself. Well that was an underestimate for sure.

But in the end - a Much improved ride and look. Its time I started driving more - so far this spring it has been new fuel pump and move it back by battery box from firewall, rebuild heater box and replace heater core, and now new springs, left damper box and new rebound straps. Its time to drive again!
R.W Anderson

What makes "BRITTEK" springs so good.Are they British Made? I need to purchase some new 6 leaf ones and would like to keep the car as orginial as possible,Thanks much,Rich
rich osterhout

I heard along the way in my searching out new springs and hearing interesting stories about quality control in current springs, that one should find some british springs. I don't know if mine were Brittek, but they came from england a few years back but never used by person I bought them from. I've heard from some that new springs in a pair weren't even the same height and of course resulted in the L & R sides being of different height when installed. It all may boil down to older metal was better, I heard the same thing when I bought brake rotors, and a vise. Quality of metal is suspect depending upon source country.
R.W Anderson

I think the best thing to do, as others have mentioned, is to have your original springs rebuilt. Bought a new set from BritTek and the car sat way too high in the rear. Also the springs were not straight longitudinally -- made the rear axle shift over to the LH side. So I had a spring shop rebuild the originals. Problems solved. If you do get a new set of springs, check them on the bench first to see if they are straight.

Tom
Tom Custer

Spoke with Bob at Brit-Tek yesterday and he said that his were made in England by the English Spring Factory????Whats a person to do?????I have 1972 MGB springs(orginial owner with 52,000 miles)Thanks,Rich
rich osterhout

Re-visit on rear springs.I would like to here from folks who have been happy with what they bought or not....along with some comments/advice
rich osterhout

Just to throw a spanner in the works, I too was fed up with having my tooth fillings loosened by multi leaf cart springs, so I experimented with RV8 parabolics on my V8 conversion. What a difference in ride quality! I still get tramp, but this might not be such a problem with an 1800. At pres I'm toying between anti tramp bars and a coil-over, trailing link conversion.
Al
Allan Reeling

I have an 80 LE still on the jackstands with total rear end rebuild including new springs from VB, performance bushings throughout, complete brake system from new brake cylinders to all lines and hope to drop it on the ground in the next few days. Some comments concern me about the new springs, but replacement was straight forward enough with no problem mating the shackles, U-bolts, etc. I'll let you know if there are any surprises when I put it on the ground. Some have mentioned differing alignment with new springs, but the 80 LE has rear anti-sway bar that should assist centering the axle without problems of one wheel being closer to the fender than the other. As I best recall, the 72 didn't have rear anti-sway bars. For shocks, I'm using the original knee action. In my experience (I used to run SCCA), they're hard to beat. Also of note, I haven't torqued down the rear shackle bolts. As I best recall, you should wait until the car is on the ground for proper settling of the bushings. I never had a bad ride, just caught the springs on sale and more an attempt to reach concours condition than improve ride or performance.
Rick Penland

I got my replacement springs from The Roadster Factory in PA and never had a problem. They were made in England. RAY
RAY

Ya know - just when I think I knew what I was doing someone makes a reference to some step in the process I never even concerned myself with.

1. A friend asked if I measured axle placement to make sure one side of the axle isn't closer than the other to the front wheels.

My response was - what placement, how can it go back but right where it is suppose to be?

Given that the front and back of the leaf spring mounts to a rigid pre-determined location on frame, the center of the leaf springs is pretty much where it should be, right under the axle.

Also, given that the U-bolts just clear going around the axle and the steel plates underneath have to line up with the U-bolts,where is there space for the axle to be out of alignment? Especially when the spring and axle are attached on the opposite side of car?

2. Torque - it was hard enough to get a ratcheting boxend wrench up on shakle that I never considered getting a torque wrench up there to torque things to specs. I didn't torque anything. I just made sure things were tight. About the only things I torque on any car are wheels and heads. In 45 years on cars, bikes and whatever, I haven't had anything come off, break, or warp due to a torque problem or lack thereof.

Oh, I take that back on nothing breaking. I quit using 1/2" drive on small stuff - tended to snap things once inawhile, but that was in the 70s; when I was stronger and younger. :)

Your thoughts?
R.W Anderson

Good questions, R.W. Looking at my completed installation, everything appears to have gone back into place correctly, at least from an "eyeball" point of view. The procedure your friend refers to is usually performed at an alignment shop with proper equipment. It might be difficult to determine if the exact angle from the center of each rear wheel is exactly 90 degrees from the corresponding point in relation to the front wheels, otherwise, your car will "dog" track as we called it. However, I agree that the alignment points are all part of the design and should leave little deviation. I searched the archives here for rear suspension torque and there is only one that is useful, the front bolt to the spring eye. The rear shackle bolts "stop" because the bolts are flanged, but torque might still be useful. The U-bolts should align correctly if taken up equally. It might be possible to misalign by tightening one nut too much before drawing up the other 3. I took it a little at a time and made sure that each end of the nuts revealed the same amount of threads on the U-bolt. In the archives, 20 lbs has been mentioned as the torque value of the U-bolt nuts, but the real measurement is the shims you're installing top and bottom of the rear leaf center. I tightened them until they just started to squeeze out and the U-bolts were stopped up about a half inch of exposed thread on each just like it was when I took them out. The measurement might vary based on the shims you're replacing and is not a "rule", but application specific to your installation. Since I did my entire front end and now my rear end and haven't been off jackstands since, I'll have alignment checked when it's back on the road for fine adjustment that I can't do.
Rick Penland

Ray,How long ago did you get your rear springs from The Roadster Factory?I nee rear springs but after reading some of these posts I'm not sure what to do.I'm orginial owner of 1972 MGB,it had 52,000 miles on it, and i dont know if I should just use my old one or replace them. They dont seem to be cracked or anything. Your Comments???????????????
rich osterhout

Rich, It was several years ago that I purchased my springs from TRF, but they have always maintained a very high level of quality in the parts that they sell. RAY
RAY

Ray,thanks.I do buy from TRF,however Dan(@TRF) said they come(rear springs)from England BUT he was not sure if they were English steel and where they were made at.I belong to their investment program ,so i do purchase from them.Also see above post.Thanks,Rich
rich osterhout

"My response was - what placement, how can it go back but right where it is suppose to be?"

Exactly so. There is only a very small tolerance for movement. The wheels are moving backwards and forwards anyway as the springs compress and expand, and at different rates as you corner and roll.
Paul Hunt

This thread was discussed between 12/05/2009 and 23/06/2009

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