Welcome to our resource for MG Car Information.
MG MGB Technical - Bulletin about jack mounting
|In the MGB General one of the participants said there was a factory bulletin in the late 1960's warning of possible failure of the jack mounting point. Has anyone information regarding this? If this is accurate it is critical for all of us to know.|
|I'd have thought the passage of 40 years rather overuled a factory bulletin. I don't imagine anyone trusts the jacking points. michael|
|Haven't seen that but I have read of a factory warning that if the jacking points (or more correctly sills) are more than 18 months old and an unknown quantity then you shouldn't use them.|
|I posted that bulletin. I had read several years ago in a well respected magazine that the factory was seeing an alarming rate of jacking point failures,i.e. sill weakness, in cars over 2 years old. When my jack pulled the jacking tube out, damaging my driver's door, I decided that when the sills were replaced the tube would be deleted to prevent this failure in the future. I, too, carry a small scissors jack in the boot for those special occassions when a jack is required. RAY|
|If the factory sent out a bulletin about "an alarming rate of failures", why did they continue using the same jacking system through 1980? The fear of litagation alone would have mandated changes.|
This is a critical issue and one that should be expressed in all MGB publications to prevent potential serious injuries to individuals and of course damage to the car. If this is a valid issue BBS should post a warning notice. I will present the information to the Northern California MG Owners Club.
|Any failure through corrosion of the sill & crossmember supporting the jacking point is unlikely to cause sudden failure.|
What usually happens is that as you jack the car up there is a crunching sound and the jack goes up while the car stays on the ground!
Nobody should EVER work under a car supported by a jack alone!
Exactly the same considerations are required if using a scissor or bottle jack - the structure of the car where the jack is placed should be in a suitable condition to support the weight of the vehicle.
|Chris at Octarine Services|
|I remember being told by a (then) Leyland dealer service manager in the early 70's that it was advised that jacking points should not be used on cars that were more than three years old. |
As for a bulletin, remember this is going back to the days before litigation lawyers had been jacked-up to a position of influence on society and the days of slippery-shouldered BMC/Leyland management where putting anything in writing that might have some comeback was unheard of.
You've only got to look at the minimalist & afterthought design of the MGB's jacking point to see they were barely adequate for the purpose even when new. Also if your car has had new cills fitted during its life there's no way of telling if the jacking reinforcement piece has been fitted inside the cill, thus it could fail on an otherwiswe rust-free car.
On a more esoteric note, have you ever carefully jacked up you car to replace a wheel on the offside only to realise your spare is locked in the boot and the keys are dangling from the ignition lock and you can't open the driver's door because of the jack?
|"why did they continue using the same jacking system through 1980"|
It wasn't a failure of the jacking point but failure of the sill due to corrosion (or inadequate repair), which the factory wasn't liable for (until they started giving anti-corrosion warranties some years later).
|My jacking tube failed. It split completely along the bottom, allowing the jack to pop out. My sills are solid.|
|When replacing the sills on my roadster a couple of years ago. I did not fit jacking points as I have seen the results of using them many times. Jack up from the chassis or suspension areas. A lot of British cars of the 60s and 70s used a similar arrangement with central or twin jacking points attached to the sills and suffered from the same problem.|
|Ditto Trevor. During the rebuild of my GT I left the jacking tubes off. I would never have used them anyway.|
|Had to throw in 2 cents. |
As some/all might know, the MGCs used the same jack and jack point. NUTS!!! While my car was restored and the jack tube was repaired or replaced, I NEVER had any plans of using it on my mgc roadster even though there may be a factory jack in the boot. Too many scissors jacks out there to choose from that are much better (in my opinion). Also do not put the stress on the side of the whole car to get both wheels off the ground to change the front. Think MGAs probably had a better jack offered new than the MGBs and MGCs.
|Never used the jack point...not a good design...|
|I've used the stock jack and jacking points on every MGB and MGC I've owned over the past 20 years. No problems whatsoever. I just used the one on my '67 BGT a couple weeks ago and the doors opened and closed just fine (needed those keys!).|
I can imagine that in the UK, rusty, weak sills are more common than here in the southwest USA, and in this case you do risk crushing the sill. It would have to be pretty bad to actually rip the jacking point off the car though! In this case I would consider the car itself unsafe to drive.
Well said, I have not had a problem with the jacking point and I have owned my car for 40 years. I also sit the jacking point inside the saddle of a floor jack to lift the side. The standard jacking point sits nicely inside the sdadle of my floor jack.
|Those original jacking points always scared the willies out of me. Never trusted them... never will. I just use a standard scissor jack. Authentic or not... I just want to fell confident in the way I jack the car. My 2 cents worth :-)|
|I originally started this thread after reading the comments from Ray. It concerned me enough to see if other B owners had experienced problems. At this point there have been 17 responses (mine included)and they range from "don't use it" to "no problem". I have to side on the no problem. I have used the factory jack with the tube as well as placing my floor jack under the tube for the past 35 years and have not experienced any problems. I have recently spoken with other B owners and none of them have had a problem. I even went to a shop that restores MGB's to have mine checked and they could not see any fractures in the welds or rust in the sills. |
For those of you who live in climates that contribute to rusting cars I can see why you should be concerned. If someone were to ask me, would I guarantee the safety of the factory jack? I would now have to respond, definitely not. The old addage "better to be safe than sorry" would apply. As for me, if I had a flat tire, I will still use the factory jack. Guess I don't believe in old addages.
|I suspect the early cars had no rustproofing to speak of. They therefore rusted from day one, inside any box section and in particular the sill, where normally the air can get to and dry out the metal. As there was no protection, this rusted quickly and therefore the jacking point, when it was needed for the first time, was already dangerously weakened. There were some amazingly rusty cars driving around when I was little in the 1960's.|
Later cars had some rust protection which caused the rust to become apparent less quickly but equally catastrophically in other parts of the car. This is where water or water and mud can collect: behind the splash plates in the wheel arches, on top of the trumpet section and so on. I expect that the sills on these cars rusted less quickly and in different places to the early cars.
It would be interesting to ask someone who worked for a BMC/Leyland garage in the 1960's and 1970's.
I have a 1976 BGT which sometimes gets mentioned on these pages which has been repaired at least twice before my current attempt. The jacking points have been fitted over a double castle section and a double cross-member which appears to be strong, despite there being a gap at the bottom of the membrane. (A previous repair was made by welding an extra castle section and cross-member over the original remains.)
|"I suspect the early cars had no rustproofing to speak of."|
Repaired cars probably have more of a problem than original, but that refers to the sills in general and not the jacking point in particular. The original bodies were dip-primed, so at least got some paint on them, even if they didn't get a top-coat. With sill replacement the front and rear wing repair panels only have about 1/8" gap between them, so unless they are treated with weld-through primer before fitting and *properly* protected afterwards they will rot through faster than the originals, I've had to replace five out of eight of these panels on my two MGBs. And as the products of corrosion take up more volume than the original metal, and start on the inside, rust can bridge the gap and start rusting the sills as well. Given the amount of space Lyndsay Porter gives to body repair and rustproofing in his books, it came as some surprise to me he completely misses these areas. Spraying Waxoyl in from above is no good as that simply bridges the gap and makes things worse as it traps moisture, whatever you use has to be liquid enough to run down the narrow gap. I use clean engine oil squirted in, after removing the trim panels behind the doors and the splash panels in the front wings, then poking card in to distribute it as best I can. It drips out afterwards so you need to place cardboard or something underneath, but that is a small price to pay.
|"I suspect the early cars had no rustproofing to speak of." |
I suspect you are right. My car was new in 1969. By 1979 it was too rusty to use and has never been on the road since then - but it will be soon !!!!!
|I have always used the jacking points on my car and never had a problem. I know it has the reinforcing brackets inside the sills because I put them there. I agree that with a car thats an unknown quantity care is needed. As noted above I would only use the points for work at the wheel changing sort of level. One thing they do let you do is to raise the car a bit to let you get a good size wood block between the hydraulic jack and front cross memeber, this them lets you get car raised enough to get the axle stands under the main fore and aft "chassis-ish" sections set to give you plenty of room underneath it.|
|You need to be careful jacking under the front crossmember. As you raise the front the bottom face of the crossmember tilts, which causes the jack to gradually slide forwards in a series of jerks. For that reason I always (trolley) jack with one of the 'tongues' of the head positioned behind the rear edge of the crossmember so the jack cannot slide forwards, hence no wood block.|
Likewise the chassis rails also tilt upwards with the front raised and I never use axle stands or a jack under them for the same reason. Depending on what I'm working on the axle stands either go under the spring pans or under the rear brackets for the inner A-arm pivot, again with one of the tongues positioned behind so it can't slide forwards.
Just my 2 penn'orth as well.
|So far so good, yes I always position the jack fore and aft so it can run in as the car lifts, which it does smoothly. I also chock the rear wheels so the car isn't going anywhere. once it's on the axle stands its stable. A car on axle stands one end is a triangle arrangement, we had a discussion once about axle stands both ends, that requires even more care IMHO as it can fold down into a lower energy state, possibly with you under it. The jack "pan" bites into the wood which locks it nicely, and the wood has enough friction to stay put on the cross member. I 100% agree that I would not get under the car in this condition, never mind anything else what if a seal failed in the jack?|
This thread was discussed between 02/03/2009 and 07/03/2009
MG MGB Technical index
This thread is from the archive. The Live MG MGB Technical BBS is active now.