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Replacing door check straps - advice needed


Stepo
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I only recently thought about the fact the doors on my 3.2 swing open very easily due to the door check strap probably breaking down over time, I believe the plastic inner parts give way as the actual bumps on the metal straps look ok.

I purchased a new set and have been told to be careful with the installation as they are very tight and the worst case scenario is extra pressure may damage the actual sheetmetal within the door which is a disaster I would like to avoid.

A mechanic told me they install the straps, then take to the bumps with a grinder to remove around 1mm from the top of each bump, thus reducing the pressure on the sheetmatel but still giving you resistance to hold the door in the three positions.  IMO, grinding will damage the yellow zinc plating and initiate rust if I don't paint them.

I also read about another method on Pelican Parts (was for a 993 but thinking it will be the same) where they open the fixture and trim 1mm off the inner plastic parts to reduce pressure which I am leaning towards rather than grinding.  I'm thinking I may also try and use my existing flat metal bars with the bumps as they are colour coded to the car, probably original?

https://www.pelicanparts.com/techarticles/pcar_com/993_door_check_strap_detent.htm

Any feedback or experience with this mod would be well received prior to me having a go at it.

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Peter,

I've only replaced one set of straps ever and I suggest you just lubricate the detents well before you install them ASSUMING that the sheet metal around where they mount in the door and the A pillar is not cracked or rusty.   I don't think reducing the detent is prudent as you then expose the door to other forms of damage such as being blown fully open on windy days or accidently being knocked onto cars parked next to yours.  The detents lose their extreme stiffness pretty quickly too.   I think the damage that 993's suffer in particular is due to the cushion at full opening breaking up and the door then coming to a sudden and un-cushioned shock of a stop.   I don't think the detents along the strap place much strain on things compared to the end stop in practice.

Where I did agonise is driving out the pin that holds the strap to the A pillar.  I found that difficult and not a lot of fun at all.  Tapping didn't move it at all!  To reinsert the pin, I connected up all the 1/2 inch socket extensions I had so that I could tap (hammer!) from above the door/mudguard.

Great idea to protect the paint on the A pillar around the pin location with lots of tape.

Frankly, because I didn't have the right tools to remove the pin it was possibly the least enjoyable job I've ever done on a 911.

 

Good luck!😉

 

     

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I had the same issue with my 3.2. It's a fine line between too slack, so that the part open stops don't work and them being too firm and adding stress to the mounts in the door.

If the bumps on the strap are too thick, then you risk tearing the door mounts, which are very thin, then you will need to get them welded or make up some metal plates to sandwich the fractured mounts.

So, definitely grind down the mounts with a file or grounder so you don't stuff  up the doors.

I have some spare check stops if you grind too much off.

Good luck

 

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14 hours ago, Peter M said:

Where I did agonise is driving out the pin that holds the strap to the A pillar.  I found that difficult and not a lot of fun at all.  Tapping didn't move it at all!  To reinsert the pin, I connected up all the 1/2 inch socket extensions I had so that I could tap (hammer!) from above the door/mudguard.    

Thanks for your feedback Peter!   I did read something on the door pin being hard to get out.  I was thinking if I could place a socket on the top of the pin that provided clearance for the head, then I would try using a small G clamp between the top of the socket and end of the pin to push the part out instead of hammering, that'll be my first attempt anyway.

 

15 hours ago, Rob H said:

I have some spare check stops if you grind too much off.

Thanks for the offer Rob, that's very kind of you, I'm hoping I don't need to call in the favour.

 

13 hours ago, Ashbaxter said:

Recently did this job and the new ones are ridiculously tight.

 My initial thought was to grind down the bumps then I found the Pelican article you mentioned.

I disassembled, trimmed the plastic bits as per the article, put it back together, installed and it worked like a charm

Ridiculously tight is an understatement Ash...….just to see how the straps work, I've tried pushing them by hand with my full weight onto a bench to move across the bumps and they don't budge, even tried a bit of targeted hammering and still no movement.  I'm pretty sure the sheetmetal in my door is in good condition and I don't want to stress it and create a nightmare.  Your feedback on plastic trimming is gold, that's what I'm going to try on the first door.

 

12 hours ago, Tips said:

My doors straps are also stuffed. Where is the best place to source the new straps?

@Stepo keen to hear if you end up using the original straps with the new plastic inserts as I would like to take a similar approach.

Hey Tips, I got my set from a local mechanic, I think design911 have them but in Syd would be checking with Autohaus.

Before considering use of the original straps, I'll be doing some check measures to see exactly how similar they are.  If there's any differences, I think moving to all new parts is the way to go as that's how they were designed to work together, although their design of the resistance in the bumps leaves a lot to be desired.

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8 hours ago, Stepo said:

Thanks for your feedback Peter!   I did read something on the door pin being hard to get out.  I was thinking if I could place a socket on the top of the pin that provided clearance for the head, then I would try using a small G clamp between the top of the socket and end of the pin to push the part out instead of hammering, that'll be my first attempt anyway.

Peter,

I actually tried to make a puller (pusher??) using a G clamp too but failed dismally.  One was the problems was not damaging the paint on the part the pins goes in to with the socket.  

 

Just hope you have much better success!

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12 minutes ago, Peter M said:

I actually tried to make a puller (pusher??) using a G clamp too but failed dismally.  One was the problems was not damaging the paint on the part the pins goes in to with the socket.

😬😬😬 TBA

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  • 3 weeks later...

I recently tackled my stuffed door check straps and can say it is one job I should've done a looooong time ago, they are so much better now.  I basically didn't have any resistance holding the door half way and the hinges could open miles out past where they should've stopped.  When I pulled the original mounts out, I noticed the steel had actually deformed at the end of the strap due to too much outward pressure.

Turns out my old units weren't fixed to the body with a knurled pin, just a socket head bolt and nyloc nut, so easy to remove and I used this system to refit, didn't use the pin supplied based on issues with fitting and removal I had heard about.

I didn't try reusing the old straps as they were narrower in width and higher on the bumps than the new set.  They wouldn't have worked in the new housing.

The original system is different to the replacement I used.  The original had steel balls that rolled along the strap surface.  The new units have plastic mouldings that push against what looks like a needle roller.

I did end up opening the housings like the link I posted and cut away just under 1mm of the rubber to limit excessive pressure on the door sheetmetal.  The doors now open very smoothly and they stop at both resistance points without creaking or opening too far.

If your door straps are gone, get onto this fix, you won't be disappointed ;).

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