Has anybody else noticed that A2 door check straps do not work?

Little Dog

A2OC Donor
European-Union
I'll post more details but basically A2 check straps do not stop the door from opening. They slow it down a little but the door stops on the stops on the hinges. This is probably the reason A2 doors fatigue.

If the check straps were a little shorter, or the nylon buffers in the mechanism a little deeper, then a door swinging open would be caught on the strap and not at the hinge. Catching on the hinge allows the door to swing further under its momentum and fatigue the door.

Thoughts?
 
@depronman uprated ones do stop the door on each notch even when on a gradient. Highly recommended.

I noticed this problem while fitting a depronman strap. Yes I agree a big improvement but they still have the same two components that are just a tad short on material or a little too long depending how you view the strap and the problem.
 
I think I have a fix for this one, well can’t fix the fatigue but can prevent it going further. Get yourself a depronman modified strap, they are good. Then loosen the aircraft bolt things and shim the strap out until the strap engages before the hinge. Sounds simple, need to sleep on it.
 
Haven’t fallen asleep yet and thought of a second solution. Grind a bit off each hinge stop to allow the check to do it’s job.
I won’t be going there though as I’ve had it with removing and replacing doors.
 
Done some investigating; this is a new N/S door opened until it stops on the hinge stops. The check strap fails to make contact with it's stops by 0.6mm at the bottom:

u4tqHts.jpg


At the top it fails to contact by a whopping 1.5mm:

3YSyM4q.jpg


That strap is coming off for modification, I'm not going to let my passengers ruin a new door. I'll make the same mod to the drivers door to stop the existing crack progressing further:

3l5CK29.jpg


The orange is the reflection of two wing mirrors stored in Salisbury's shopping bags, I just know somebody will ask :)
 
The imbalance of the gap will be due to the check strap mounting not being perfectly square. There is adjustment room on the two mounting bolts
Suggest putting heat shrink around the T end of the strap bar


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The imbalance of the gap will be due to the check strap mounting not being perfectly square. There is adjustment room on the two mounting bolts
Suggest putting heat shrink around the T end of the strap bar


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Hi Paul
I was thinking about asking you to make 2 straps for my 1.4. Is there a way you could modify your design to avoid the issue mentioned above?
Being a low level engineer, I admire what you can achieve, so please don't take it wrong, I don't really know what it does take to do that.
Thanks
 
yes sure, the end of the strap rod is a T shape, it is the cross on the T which its the bump stop on the check strap, by adding a couple of layers of heat shrink tube the 0.6mm gap (around 1mm gap when evened up) will be taken up by the heat shrink tube, The tube is hard so should wear well
Just remind me when you order the straps that you want the heat shrink fitting

No extra charge (25 quid each strap) plus 20 quid deposit which is refunded when I get your old straps back and 3 quid postage

Cheers,
Paul
 
If you want to send me your own for refurb I have no problem with that but you will not be able to safely use the A2 with no check straps
This is why I provide refurbished straps that you fit and then send me the old straps of you car. These are then refurbished ready for the next customer
If you are sending me your own straps then the deposit is not charged

Cheers. Paul


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If your door strap is not working at all you can remove white nylon buffer and replace it or just turn it over because on side of the buffer probably is still good. I turned it over and strap is working again.
 
The imbalance of the gap will be due to the check strap mounting not being perfectly square. There is adjustment room on the two mounting bolts
Suggest putting heat shrink around the T end of the strap bar.

Sent from my iPhone using Tapatalk

Good point Paul, I’ll make sure I goes back on square.
I guess I will then have an average gap of 1mm? Already bought 1mm aluminium for my shim so will also use heat shrink as your suggestion.

As Vic as suggested I’ll look at turning the stop over but judging by the wear to my hinges and the gap I suspect my stop has never been used.

Thanks all for your contributions.
 
I'm unsure what Vic is referring to as the buffer as it is more of a light yellow in colour, the rollers are certainly white
The yellowish buffer will only fit one way as there are little fingers on the top that prevent the two free ends of the buffer splaying out, if it was to be turned over these fingers would have to be removed, plus from memory there is a shape to the top surface.
If Vic is referring to turning the white roller over (as the strap tends to run on one end of the roller) then that is nothing to do with the buffer (a better name would be 'end stop') These white rollers are what are replaced with brass rollers on my check straps

I had another thought, is there not enough movement or adjustment on the mounting bolts of the check strap to door to remove this 1mm gap ?
filling the holes into an oval shape could be done to allow more alignment wiggle room and would be an easier fix than shimming
Cheers,
Paul
 
Sorry for misunderstanding for terminology, my english is not perfect.

I am talking about theese:

m29_1485887296136.png
 
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Sorry for misunderstanding for terminology, my english is not perfect.

I was talking about theese:

View attachment 44703

It’s OK Vic. Those are the rollers that wear and become distorted. I guess you can turn them over or alternatively send the assembly to depronman, who for a reasonable fee, will replace the plastic rollers with brass rollers. Gives the door opening action a much more positive feel.
I now have both my front door check straps working. Details later.
 
Right done some checking, the clearance holes on my strap assembly to door holes are 6.4mm dia which does not give much movement on two M6 studs not too far apart. I've concluded that the difference between the top and lower stop, detailed above, is down to bad stud positioning on the door. So I have a minimum gap between the strap and stop of 0.6mm but the amount of packing I can use is restricted to a fraction over 1mm by the gap between the strap mechanism and the mounting casting:

kN0Gr9y.jpg


I've decided to accept the check will only catch on the lower side of the T and shim out by 1mm:

e2ZxPMf.jpg


Shim made:

NMfY4iI.jpg


Had to deal with rivets with a hollow center for the first time. Drill them and they spin, chiseled the head off and drifted out what was left. Thinking afterwards I could perhaps have drifted the whole rivet out from the underside. Reassembled with socket cap screws (hopefully they will clear the door card) and fitted to the car. Check strap and hinge engaged simultaneously so off again and shrank two layers of shrink tube onto the strap T:

VHdoXvQ.jpg


One the car, again and jobs a good un; swing the door and the A post can be seen to twist. Hinge stops do not engage, new door protected from fatigue:

xzYIYIR.jpg


The drivers door is much easier, the door studs are correctly positioned and I have depronman modified check strap. Make a shim:

yutcbyJ.jpg


Loosen the screws a little and tap in the shim:

4EtBzw5.jpg


Tighten screws and job done, again the door is catching on the check strap and fingers crossed the door should not be subject to any further fatigue:

REAj7U5.jpg
 
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Hello
I will at some point ask Paul @depronman to send me 2 of his straps.
What would happen if you insert a thicker shim?
Thanks for the above detailed tips
 
Hello
I will at some point ask Paul @depronman to send me 2 of his straps.
What would happen if you insert a thicker shim?
Thanks for the above detailed tips

Eventually the nylon buffer will clash with the casting that mounts on the door, see my first picture. When the assembly was riveted the gap was a fraction over 1mm hence my choice of a 1mm shim. However screws pull the assembly together tighter and I suspect I could have squeezed in a further 0.5mm.
1mm though is the max you can insert into one of Paul’s straps without having to fit longer screws.
 
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