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MG Midget and Sprite Technical - Soft top front bar lifts at speed

Using the Frogeye (IOW) everyday for work at the moment and having hardly ever had the roof up, have encountered a problem. The front rail is secured by a stud at either end and the rail is held tight against the top of the windscreen frame by the tension of the hood. Unfortunately at speeds much above 50mph the rail pings off slightly, letting icy wind rush into the cockpit. While it doesn't actuually fly back because the studs hold it on I end up gripping it until I can slow down and force it back over the top of the windscreen, which is cold and dangerous.
Has anyone else encountered this problem?
The hood is in good condition - looks quite new. and the inner hoops keep it quite tight.
Any suggestions greatly appreciated.
C Whiting

possibly a photo required of the front rail
Nigel Atkins

I can certainly do that at some stage, but it's dark when I go to work and dark when I get back, so a bit difficult at the moment. It's a flat bar sewn into the hood about three quarters of an inch deep which hooks under the front edge of the frame and tilts downwards.
If I can use a torch and my wife's posh camera I might go and take the cover off and have a go now. Will post as soon as I get a reasonable shot.
C Whiting

Right. Failed miserably. Four second exposure and the slightest movement blurrs it, so I'll have to wait for daylight.
Looking at the way the thin bar slips under the slot makes me wonder whether I would get a better result putting the front on first rather than the rear studs which I've been doing first because it was a lot easier single-handed - I was doing back on first, then leaning on the roof both sides to push the interior frame tube sliders down, then attaching the front bar, then the front studs (a very tight pull) then raising the sliders and tightening with the bit that raises into the centre of the hood.
Is that the wrong way to do it? None of my books makes any mention of correct procedure so I might well have been doing it wrong. I collected the car last winter with the hood up and drove it 180 miles at speed and it didn't lift then, so it looks as if I must be doing something daft.
C Whiting

had it on the frog i borrowed for the 'summer', turned out i had just not tucked the sewn in strip - in far enough!
Mick - still wiring!!

Common problem on the Mark I and II Sprites and the Mark I midget. I suspect they changed the design of the top with the Mark III since both the MGA and MGB had a better hold down mechanism. I used to shim the section of the top, where it holds the steel bar stock and "hooks" into the channel on the front of the windscreen, using pieces of cardboard. It helped some, but the basic problem is poor design. Both the factory top (I had the car in 68) and the replacement top evidenced the same problem. Anything to make the tuck in piece fit fully, but tightly, would help cut down on the problem.

Les
Les Bengtson

This is going to read more complicated than it is in reality but trust me on this.

The book says do it from the back first then attach the fromt after. However I've always found that the best way to do it is do up the front studs first then fit the front sewn in bar under the lip of the windscreen so that it sits tigh. If you are in any doubt whether it's seated in the groove properly, get your hand under the soft top from the inside of the screen and try to lift it up. If it lifts away from the screen then it isn't seated properly.
Pull the soft top over the frame (with the springs in the compressed position.
Pull one side the rear of the soft top into one of the rear teardrop slots then the other. Depending on how cold a day it is depends on how difficult this is.
attatch the other rear studs and turn buckles. Get into the car and pull the bar forwards to tension the soft top. If necessary then twist the uprights of the hood frame to further tension the roof.
I have had no problems with the front of the soft top lifting with speeds in excess of 110mph
a final tip. If it's a cold day and you are running with the top off, store the soft top in the passenger footwell so that it stays nice and warm in case you have to put it up. The warmer the top, the easier it is to put on.

Phew!
Gary & Gaps

I remember my MKI Midget hood would come unstuck around 70mph; the sewn-in strip would give up as reliably as clockwork. This was summer of 1974.

I hope Gary's method does the job!

A
Anthony Cutler

Gary - that's just how i did the borrowed one in the end!
Mick - still wiring!!

Many thanks for all this. I reckon I will go the Gary and Gaps route and try fitting front first. Pinged out at 45mph on the way home tonight. Temperature issue is interesting - I have seldom used the roof but with daughter needing the family Clio it's my only transport, and it was below freezing when I put hood up a few days ago.
Just been and sat in it in the dark and even though front rail is back in place, I can feel from inside that it is not seated properly in the groove, and no amount of squeezing and levering will make it sit deeper.
Roof is good and tight, but that rail just won't hold in.
Perhaps I should take roof off tonight and stick it by the fire, although I'm not sure I really want to fit it in the dark tomorrow morning.
All advice much appreciated - daylight and warmth is all I need now.
I won't however be testing it at 110mph - if it stays on at 70 I will be delighted.
C Whiting

Is the front rail sew onto the soft top straight?
Is the locating lip in the front of the windscreen bent up a bit too much?
The fact that you said that it was ok when you collected the car makes me think that either it's being put on incorrectly (easy to do), or the metal strip sewn into the top has somehow twisted into the wrong position (although I don't know if that's possible).
I'm MoT'ing the frog tomorrow so will get some images of mine in situ.

Are you coming on the bridges run on the 2nd of January, If so we can have a collective swarm over you car.
Gary & Gaps

I don't think the hood or rail has changed since I bought the car, although it was outdoors all summer, albeit folded neatly in a sack under cover - I suspect I am fitting it wrongly, or when it is too cold to stretch properly.
Hoped to get to Bridges run, but it now looks as if I will be working on January 2nd, unless I can swap shifts with some other poor hack.
Picture of yours in situ would be most useful.
Many thanks.
C Whiting

sounds like it might have benefited from being put up and stretching out in the heat of the summer and packed away for driving and again put up in the heat cycling this through the autumn and into winter

this also 'stretches' out the frame plus you get the practice of raising and packing away

bit like the whole car regular use will keep it at it from 'stiffening up'

keep at it it will ease up - soon be spring to
Nigel Atkins

MGAs also suffered from a similar problem , they added a latch in the center of the upper bar of the windscreen and the front bar of the hood. I suppose you could do the same, might even use the MGA parts. Items 13 and 14 in the drawing. http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=809
B Young

Bill,

It shouldn't need a latch or any kind of additional fixing. If everything is ok it will work perfectly up to and beyong the maximum speed of the car.

By the way, mine just passed its MOT with no advisories. I'm delighted.
Gary & Gaps

Gary, I'm sure you're correct, but since it's an IOW car I though the bits might be a little different from the standard Spridget and might need some additional help. Congratulations on the MOT! We're so lucky here in the US not to have such restrictive inspections although there are a lot of cars on the road that probably shouldn't be because of that laxity. I'm sure that those of us with classics maintain our cars to a standard that is usually above average anyway though. I changed to vintage plates on my Midget last year, some mileage restrictions and I have to carry a log book of my travels, but no more inspections every year to worry about. I plan on registering the Lotus the same way.
B Young

I think if you slide the bar out of the hood it's worth checking the fit and profile inside the header. On mine I over profiled it so the corners hang down slightly. This makes the center tight inside the header and prevents any popping out. I also assemble the front first.
F Pollock

Thanks Fergus - I'll try that as well, although from memory the bar is well stitched in. Hood is indoors now warming up in readiness for refitting from front back.
C Whiting

I did have the same problems with the soft top, especially with a strong crosswind and above 75 mph. What did I do? I glued some silicone on the outside of fabric tube where the bar goes in so it was thicker and less smooth, that helped a bit but did not cure the pop out. I made a thicker aluminium bar; in fact I did put 2 bars in, each 2 mm x 15 mm. Popping out is cured. I experimented with the shape. The profile is not definite the best. At the corners still some water drips while driving in heavy showers.
Gerry I saw your superior soft-top at le Mans last year. Where did you order it? What is the profile and what are the dimensions of the bar? My original soft-top is 53 years old, has no tension and will soon be beyond repair.

Flip



Flip Brühl 948 frog 59

Thanks for all the help - problems solved, I think. It wasn't properly slotted in. Pete Jones and I tried the front-first approach, and managed to get bar much further in, although there is a surprising amount of movement/slack between the windscreen glass and ally frame at the top. Pushing the glass back slightly enabled the bar to slot in as it should, and it stayed firm at 75mph on the way back.
If it comes out again I'll have a go at the re-profiling suggestion, but unlike Gary I'm not planning on testing it at 115mph so I reckon it'll be fine.
C Whiting

If I've understood you correctly you are saying that the front strip has slotted in between the glass and the ally frame. That doesn't sound right. The glass shouldn't move back, it should slot into the top lip of the frame not between the glass and the frame. However if it is staying put at 75 mph then no worries.
Gary & Gaps

Ignore what I just wrote. I'm talking rubbish (again)
here is an image which shows mine (press studs unpressed). Ingnore my cracking windscreen seal.


Gary & Gaps

and the other side. I really must repaint the metal strip and centralise it.


Gary & Gaps

Good God. Looks like the underbelly of a Pterodactyl after a particularly miserable wet prehistoric summer. Terrifying creases and flaps. But then again, it doesn't pop out at 110. Perhaps it is just the cracking windscreen seal which leaves the primeval swamp impression.
Very useful pictures though - I definately did not have my bar wedged in far enough and there is a considerable amount of movement between the glass and frame, which does not appear to be a problem with the hood bar jammed in properly. It opens the space up. Never noticed this without the hood up, which is how I usually drive.
C Whiting

This thread was discussed between 20/12/2011 and 02/01/2012

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