Central Locking Vacuum Element Recovery

[djenka018]

For all of you who wanted to get your central locking fixed but did not find the replacement diaphragm... well... have it fixed this way.
First time I've tried it 5 yrs ago on the backrest locks on my 1980 450SLC and guess what... they still hold vacuum 100%.

Pics are self explanatory.
In addition to pics, I'll just mention that it is paramount importance that you keep inner side of diaphragm free of glue.
For those fully thorn top ends, apply glue separately to outer side of the both torn element pieces and, when dried to the touch, position the parts in as close to original position as you can. Buildup of glue thereafter will create a seal. Patience and multiple thin layers lead to success.

Drying time between layers is minimum 24hrs and expect at least 3-4 layers of glue before total tear will be patched. Small tears will be good in 2-3 layers. Non torn pieces will be protected from further tears in 1-2 layers.
To have bubble free layers, pour glue into a little container, thin it and apply it with a brush on a dry day. Humidity produces more bubbles... but it will work anyway.

Try not to articulate diaphragm until glue have completely set and is totally dried to the touch. Once you're happy with new "seal" I suggest touching it with dusty hands to remove any surface adhesion (as it may create pinch effect). If some glue went on the inner side, clean it before use or it may fuse diaphragm to the body.

Glue type may be critical, please find as close alternative as you can. Washing all the diaphragms in water and solvent like lacquer thinners and perhaps some sandpaper application will make the whole deal longer lasting.

Usual PPE as per MSDS should be worn during the whole procedure.
If you do not know what PPE and MSDS is, google it or perhaps look up on wikipedia

This is dried up ready to be used element:


Glue still setting:


Not ready yet. This was a full tear of the diaphragm


Magic in the tube:


EDIT:
Some sense and further description added

[WrightSounds]

Awesome. Thanks for the pics and info. I have my fuel flap actuator out right now because the rubber diaphragm is leaking. Definitely going to try this especially since I was thinking there has to be a similar way to do the repair. I was thinking along the lines of a bike innertube which led me to a post about using old innertubes as a replacement diaphragm. Your technique looks pretty great. Thanks again!

Matt

[Tony66_au]

DIY Diaphram!

I used Tarzan grip to do similar but I believe that any rubber cement should do the trick.

As a matter of interest did you buy that Loctite contact recently?

Coz that Toluene percentage is insane and Toluene is a nasty carcinogen amongst other thing.

[djenka018]

DIY Diaphram!

I used Tarzan grip to do similar but I believe that any rubber cement should do the trick.

As a matter of interest did you buy that Loctite contact recently?

Coz that Toluene percentage is insane and Toluene is a nasty carcinogen amongst other thing.

I've heard the same from so many different sources for both, toluene/toluol and MEK, but I was unable to find any official document supporting their extreme carcinogenic nature claims. I sure do not think they're healthy hence the PPE and MSDS reference in OT.

I like MEK and Toluene for their nature of fusing plastic and many different materials... no glue alone can do the same. In my experience, this glue makes strongest bond to the rubber and forms strong flexible layer that substitutes missing parts along tears.

I got Loctite from Supercheap Auto just last week @ $9.90

[Tony66_au]

It isnt as toxic as the various organic solvents it replaced but repeated exposure is an issue.

It also depends on how it was produced and from which source as part of one of the processes involves an organochlorine.

Id say as its use has increased in the production and substitution of far worse nasties that they have refined the stuff to a lower toxicity and my research just now sort of confirms this.

As always Nitrile gloves, good ventillation and a read of the Material Safety Data Sheets is in order.

And for what its worth Toluene is why Kwik Grip is so popular for chroming and huffing.

A nice fix for a common issue too