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MG TD TF 1500 - TF new rear springs sagging
|I fitted new TF rear springs from Moss to my 55 TF and only have 1" clearance between the bump stop on the LH side and 1 1/2" clearance on the RH side. When I drive the car it bottoms out a lot of the time. I have converted the rear axle to a banjo MGB and relocated the spring perches but that should make no difference. |
Does anyone know the standard measurement between the bump stop and top of the axle.
Any advice welcome.
|Do you have your rear spring shackles the right way arrround?|
|THAT SPRING SURE LOOKS FLAT,,, ALMOST A REVERSE ARCH AT THE FRONT ????|
|Boy it sure does look flat!|
|Andy, when did you stop tightening up the nuts on the u-bolts? It's most unusual to see that much thread below the lock nut. Are the rear shackle plates tilted down toward the front? Did you put the MGA buffer plates on the top of the axles? Bud|
|When you installed the springs and shackles, did you remember to tighten the shackle bolts?...Looks like they may have turned the wrong way (as previously noted).|
Is there a 500lb gorilla in the tub? (LOL, sorry , couldn't resist).
|Andy, I have a TD rather than a TF and I know the springs are different, but I have a clear 3" between the top of the axle and the rubber bump stop. The springs have a slight downward curvature and the shakles are vertical. Your springs look as though they have a slight upward curvature. Did you check the spring camber before installing them? Matt|
|I am thinking I have about 3" also and those look very flat. Something is not right.|
(Even with 2 gorilla's)
I'll get under mine tomorrow and post a pic if we don't come up with a cure by then.
Here is a similar photo, similar angle, on my L rear TF spring, looking rearward. I have 3 inches between axle body and the top rubber bumper. I have had no problems with bottoming out. My springs look fairly flat, though perhaps yours are flatter.
Bud, Dave Braun talks about the shorter/longer U bolts on his site. Mine are replacement from Moss. More spare bolt below the nuts. I wish I did not have so much "extra".
Andy, are you saying you have installed a MGB axle, or only the gears? If the whole axle, that must make things different back there.
|Hi guys and thanks for your comments. I've attached another photo that shows the rear shackle and it looks like Tom's photo. The bushings were new. The axle is a 3.9 MGB banjo and I used the mgb top collar plate and lower spring perch which was cut off and welded back on using a jig from the TF axle to ensure it was square and tilted correctly for the drive shaft. I reused the TF U bolts and TF bottom plate, everything fitted great even better than before. I must agree that the springs look very flat; perhaps I got bad springs from Moss.|
There are no gorillas in the family!
Here's another similar photo of my TF.
(I love my iphone).
Let me know if you want any other photos, by email. No problem taking more.
I don't hold my TF up to being perfect, but rear suspension function is as good as I can imagine.
|The MGB axle tube diameter looks to be greater than that of the TF tube. Perhaps that contributes to the reduction of the space between the top of the tube and the bumper. Just a thought.|
|Definitely looks like it's spring related...in the photos that Tom provided the axle housing looks like it's midway between the bump stop and the check-strap...in Andy's photo it's definitely closer to the bump stop.|
|I still think it is in the sagging springs,,, but compare a measurement from the top of the spring to the bottom of the axle tube on your car with some one elses which has a stock TF axle,,,,|
|Hi guys thanks for all your comments and advice. I've ordered new rear springs from Moss and will let you know how they work out. I need to install them before the drive down to GOF on June 18.|
|Is it possible the shock arm has something to do with this? i.e. is that a TF shock arm on one off a MGB? |
I won't get home for a few days to post a pic of mine, but when I do ...should I also measure the shock arm for you?
|Hi All, As I recall I had the same problem with my |
TF1500 back in the late 50's. Removed the springs and had them re-arched. Owned the car for more than twenty years after that and had no problems.
Could it just be possible that there is an error in the specs for the arch and the spring makers are making them to the wrong specs.
Just a thought.
|Andy - - I am in the middle of installing a MGB banjo axle in my TD. I noticed on your first photo, that you are not using the MGB hand brake system. Did you flip the backing plates to bring the hand brake levers to the front side of the axle? Is so, how did you connect to the TD/TF twin hand brake cables? Any photos you might have would be very helpful. Thanks - Lou VanK.|
|Lou Van Koningsveld|
Snapped a pic for you as promissed.
Not as much "gap" as I thought there was.
I haven't been under the car with it on the ground for quite a while. Mostly see it now when on the lift. Can only recall bottoming out a few times and that was under some pretty bad road condictions.
(Really bad RR tracks I hit going a bit too fast.)
|Just for the record. I too fitted new Moss springs in March 2011. I've done about 500 miles since getting back on the road in April 2012 and my springs are flat just like Andy's. I also fitted new Moss shock arms and the thread length on the U bolts is the same as Andy's.|
Looking at the back of my car, I also noticed that one side is lower by about 1/2" although the distance from the underside of the shock link brackets to the ground is the same on each side. This points to one spring being "flatter" than the other which you can just about see. And yes, I have checked the angle of dangle on the shackles!
Wish I had got my old springs re-arched now. Seems to me like you can't buy decent parts anymore. I guess the suppliers realise that we don't put a lot of miles on the cars and are prepared to put up with inferior quality.
ps Don't talk to me about the rubber bushes!!!
|A R Jones|
I installed the MGB rear in our TD, and it came out great, but we have a supercharger. Cruises great on the highway, but not much power way down on the power curve. Hopefully, your TF has enough power to run like 3500 rpm @ 70 mph. I plan to get a cam from Len Fanelli soon to go in a supercharged 1466 cc XPAG... it needs all the low end power it can get.
My opinion is the springs are your problem, like no arch or someone assembled some leafs (leaves?) upside down. Longer shackles might get you by temporarily. Used springs would probably be a big improvement.
I'm curious about the rods, one in front and one in back, apparently. Is that a Watt's linkage? ...and why?
The brackets look too flimsy for that or track bars.
It does not appear that your hand brake is connected, or does that rod (conduit?) have something to do with it? ...again, one in front and one in back?
I did flip backing plates upsidedown so wheel cylinders are at the top (it helps to bleed the system!) and hand brake levers are in front, low. Fabricated brackets are welded on, but don't remember to what exactly. Crawl under and have a look next get-together!
|Wish we could edit out dumb comments. I see now both pictures are looking back at the rear- had to put on 2 pair of glasses to focus on details.|
Attached is picture of our rear spring, as best I could get wiggling under the car with a camera. Seems to have about 2" clearance above and below axle. This car has a storage compartment behind axle with the battery, so I had shifted some weight to the back. It does bottom out once in a while, and I plan to address that issue. Note the square plate above the spring. This car came with "AIR LIFT" inflatable rubber helper springs. Wished I could find some replacements, but they'd probably be dry rotted. I'm going to check out some plumbing "test balls" to use as replacements. I did reinstall the air bags in front, just for looks.
Still wondering, is that conduit for hand brake cables? My hand brake cable bracket will follow next post.
|Image of hand-brake cable bracket, attached.|
Slightly different view follows, with description...
|Jim N. (MI)|
I don't understand your comment re no power with the blower. I have the new Eaton-type blower with a MGA 4.3 rear and Skyhook 5-speed tranny. Except for a flat spot at 3K RPM on a hill, it runs right through the RPM's in all gears strong like bull. Have you had your dizzy curved and what size carb are you running.
Jim N. (NY)
|Approximate dimensions- bracket is 1 1/4" x 1/4" flatstock, 5" long. Around a 30 bend at the 2"/3" location. A tab, about 1 1/2" x 3/4" x 3/16" (maybe 1/8") welded onto 3" portion of bracket. There are 3 holes drilled for the cable, affording some gross adjustment.|
I recall hammering the 2" end into the rear end, so it wedged lightly in between axle tube and spring perch, then tack welded on the sides.
They get the job done!
|Jim N. (NY)|
This isn't a complaint about supercharged power, it is a warning to anyone who thinks about installing an MGB rear end in with a stock XPAG, they may be in for a rude awakening, like "my getup and go, got up and went!" This is why the 4.30 ratio is so popular.
You made my point for me... even with a new blower "Except for a flat spot at 3K RPM on a hill," and you get to downshift into 4th. How would that run without the blower?
I'm posting the XPAG power diagrams . At 3 grand in 5th, you're doing about 60mph and showing maybe 4-5 pounds boost, right? That would still be less than 45 horsepower (unless you've gone to a hotter cam, etc, but not much more). Now a stock 1250 would have just about 35 horses on tap.
My wife cruises 80mph with no problem at 4k, but there's only about 55 horses behind that, not much much left for hitting a steep hill or strong headwinds. I prefer cruising at these lower rpms than we did before with the 5.12 rear ends, but I wouldn't enjoy it normally aspirated on 1250 cc.
The "correct" engine for wifey's toy is already punched to 1466cc, and I'm picking up a billet crank from Moldex next month, will dye check the rods and have them shot peened, and install one of Len's roller cams in soon, and of course, clamp on the Magnacharger.
Did you catch all that, Andy?
Jim N. (MI)
|Hi Guys I removed the old springs (which were new from Moss about one year ago). The LH spring (1" clearance) was made in India. The RH spring (1 1/2" clearance) was made in UK. Both came from Moss at the same time. New springs arrived today from Moss. Would you believe that one spring is made in India and the other one made in UK. What's going on here?|
I installed them on the car and put the UK one on the LH and the India one on the RH. I now have 1 1/4" clearance on the LH and 1 5/8" clearance on the RH. So things have not improved much at all.
In answer to some questions:
James-The MGB banjo axle is 1/4" deeper than the TF axle so reduction would 1/8".
David- Both shocks are TF ones and rebuilt by Peter Cauldwell.
Lou-I flip flopped the back plates and made a bracket like yours to fit the TF handbrake cables. They work great. See attached photo.
Jim the bars you see in the photos are the black vinyl coated handbrake cables not a watts linkage.
I still don't know what to do. I phoned Moss today and they didn't return my call. I'll probably drive the car as is down to GOF at Buellton but that's over 7 hrs from where I live.
BTW the person who designed the front leaf spring mount must have been a sadistic bugger.
|Jim and others something that I did not mention about my TF is that it has a Volvo B18 engine which puts out around 98 bhp. That's why I can use the 3.9 rear end. |
I would not recommend the 3.9 rear end to any stock TF 1500. A good set up is the Sierra 5 speed box and a MGA 4.3 rear end. Which is what I have in by MGA 1600 Coupe.
First sound out of my mouth was "whew!!!". You did all that TODAY? You must be young. Fast worker... you go man!
I had a similar issue with a Moss product last year. I bought a new generator. The first one was made in India, but had some issues prompting me to return it. The second one was also made in India, but was clearly made in a different plant. Many details were different, and the first one failed in a minute. The second one worked perfectly.
Good luck Andy.
Short term- temp "bandaid" might be a couple pieces of flatstock, cut & drilled for longer "Mickey Mouse" spring shackles in back.
Long term- get some used springs.
By the way, where are your old ones?
I might disassemble the springs and rebend the leafs with a "rose bud" torch, and maybe even slip in an extra leaf, but I do crazy stuff like that.*
* (welding engineer)
|The TF WSM clearly states |
"Working load - 397 pounds at nil camber"
"Camber (free) 2.85in."
7 leaves at 7/32 each
So measure up and see watcha got, watcha got.
If the free camber is right, I would guess that the leaves are too thin - this is the most tolerance sensitive dimension by far. If I had two sets of springs and didn't intend wrapping one set around somebody's ears, I would take the top full length/no eye leaf from the spare set and fit it into the springs I'm using. They'll not notice if you put the donor spring back together sans leaf to beat them to death.
It is a characteristic of steel that size is the only determinant of spring characteristics. If it was not heat treated right, it might yield and permanently deform, but until it does it will work as designed.
If the steel is as specified, find an old (very) Hot Rod Magazine, and read about re-arching springs. Or a Blacksmith.
If your conversion or some other change has resulted in more weight in back, you compensate with more arch for initial conditions, or more leaves for stiffer springs. Or some o' dis, some o' dat.
|Andy and Jim N. - Thanks for your photos. I know now what I need to do. I had planned on using a pair of refurbished MGBGT springs, but even though the overall length is about the same, the distance to the indexing pin is about 4 inches different, so I had to redo my TD springs. Here is a before and after shot. Lou VanK
|Lou Van Koningsveld|
|Note that TD springs are quite different to TF ones.|
Free camber: 4.1 in
Working load 500lb at 1/2in positive camber
Leaves as TF, 7x 7/32"
Note that MGB springs are wider - 1 3/4 vs 1 1/2.
Other specs vary by year, but the WSM does not give free or laden camber, so it is useless.
|Here is the after - Lou
|Lou Van Koningsveld|
|Tom I have a four post lift which makes life a little easier and your not lieing on your back on cold concrete I'm too old for that kind of stuff.|
FRM thanks for your comments and input. I don't understand what "working load - 397 pounds at nil camber" means. If the car weighs 1932 lbs and is 50/50 weight distribution then each corner would have 483 lbs more or less.
If the working load is 397 lbs the spring would always be sagging, prior to adding any more load to the car, or am I missing something.
The free camber on my old springs were 2.5" (india) 2.7" (UK). They have 8 leaves counting the short bottom one and measure 7/32" each for a total of 1 3/4".
I like your idea of cannibalizing the old springs to make the other ones stronger; BTW the car is lighter with the Volvo engine and MGB rear axle but only by about 40 lbs.
The numbers are certainly a bit odd. One would think that "working load" is the load on the springs in the car at "kerb weight". But the "unladen" weights for TD/TF are 2072/1932, with the "laden with two passengers" weights are identical at 2464lb I guess passengers got fatter that year, or had more crap!
The 397 lbs may have been picked as a number giving a nice flat spring for checking, but I would then call it a "checking weight". If the actual load is then greater than the check weight, the spring would have a static negative camber, not an unknown situation by any means.
The "unladen" weights lead you to think the TF is 140 lbs lighter, which accounts for a fair amount of the difference in "working load", if it is all on the back. While I too use 50/50 as "about right" for distribution, I do not in fact KNOW that either car is 50/50, or if they are the same. And I am surprised that the weights are so different. Somebody needs to actually corner weigh some cars! (and parts - like rear axles)
The only thing I trust (more or less) is the flat declaration of camber at load.
That and the fact that you are bottoming means you have to do something.
I've done the donor spring thing many times (a pile of dead springs to prove it!). Only caveat is that many of these cars are relatively too stiff at the rear, so handling might suffer. I personally like stiff suspension, and can deal with over/under steer changes pretty readily, so it has not been an issue.
Bottom plate doesn't count.
This thread was discussed between 07/06/2012 and 12/06/2012
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