CIS pressure regulator (WUR) rebuild kits

[mopydick]

Hi All,

I'm rebuilding a 81-83 SC WUR (warm up regulator): Bosch 0 438 140 090

Rebuild kit selection is very confusing and price differences are substantial.

And as far as I can tell, they all appear to have the same components. The metal diaphragm is the only part that maybe is different in thickness ??? but I don't have any reason to believe this. Everything else is just fasteners, O-rings, and gaskets.

Of the 5 kits shown below, only one explicitly says its for a 090 but all kits sure seem to be very similar.

Anyone else sort through the confusion and could recommend a kit?

Thanks,

Thurmond

$38 kit


$27 kit + $20 ship from Australia


$50 kit - seller confirmed via email that this will fit a 090


$50 kit


$90 kit - explicitly states that its for a 090, includes extra diaphram that is not needed

[coomo]

IF you are going to DIY,use the Kjet kit.However, for a proper job that will be within factory specs,send the WUR to Kjet.Trust me,Ive tried a few times to do this.Unless you have the correct Bosch test gear, your pissing in the wind.
We had a 924 turbo freshly restored that was a bad starter, despite everything being refurbed.Only after sending WUR to Kjet, it fired up first turn.

[Reiver]

Agree on the testing issue... for the Euro's it is extremely important for proper running as the WUR controls enrichment / AFR

[boyt911sc]

Originally Posted by mopydick

Hi All,

I'm rebuilding a 81-83 SC WUR (warm up regulator): Bosch 0 438 140 090

Rebuild kit selection is very confusing and price differences are substantial.

And as far as I can tell, they all appear to have the same components. The metal diaphragm is the only part that maybe is different in thickness ??? but I don't have any reason to believe this. Everything else is just fasteners, O-rings, and gaskets.

Of the 5 kits shown below, only one explicitly says its for a 090 but all kits sure seem to be very similar.

Anyone else sort through the confusion and could recommend a kit?

Thanks,

Thurmond

$38 kit


$27 kit + $20 ship from Australia


$50 kit - seller confirmed via email that this will fit a 090


$50 kit


$90 kit - explicitly states that its for a 090, includes extra diaphram that is not needed

Thurmond,

Those different kits are lacking critical components needed to perform a good WUR rebuild. Using those kits will not guarantee you to fix the control pressures problem. As a matter of fact, you could be buying the wrong kit as evidence of the last kit. WUR-090 is a non-vacuum assisted WUR , so why would you have a vacuum diaphragm in the kit included?

Tony

[mopydick]

I was hoping you'd (Tony) would chime in.

As for the last kit shown, I agree that the additional diaphragm is not needed. The odd thing is that this kit was the only one that explicitly listed the 090 WUR exclusively. The other kits did not list the 090.

As to the missing components in the kits, could you elaborate? It seems like the critical, wear components would be the main thin metal diaphragm, sealing washers and the O-rings. The other fasteners are nice to have but not really necessary (provided that the WUR didn't put up too much of a fight releasing its screws).

Thanks for the responses,

Thurmond

[RarlyL8]

What is the most common failure on a WUR? The electric bimetallic strip. If you don't replace that you haven't done anything but take it apart and put it back together.

[mopydick]

My bi-metallic strip hasn't failed.

I'm bringing an old WUR back to life that appears to be suffering from old gas gumming it up or some debris blocking fluid flow.

So disassembly, cleaning, renewing seals, is appropriate in my case.

If bi-metallic strips are such a common failure item, I would have thought they'd be part of a rebuild kit and/or available elsewhere.

[Ian Comerford]

I would have thought gumming/blocking up with all sorts of debris over the years is one of the most common failure modes

[Ian Comerford]

Before and after on mine

[boyt911sc]

Originally Posted by Ian Comerford

I would have thought gumming/blocking up with all sorts of debris over the years is one of the most common failure modes

Ian,

You are indeed correct and agree with your observation. Fuel flow restriction is one of the most common problem you will encounter with an out of spec WUR. While there are other culprits, flow restriction is the most pervasive and rampant culprit you will encounter.

Tony

[Tom F2]

Originally Posted by RarlyL8

What is the most common failure on a WUR? The electric bimetallic strip. If you don't replace that you haven't done anything but take it apart and put it back together.

Is the bimetallic strip/heater available as a separate part? Also, how many versions of the bimetallic strip/heater are there?

[Walt Fricke]

They are - Tony could tell you which is which, as some later ones got fancier, but I'm not sure it is actually better. Use the search function here, and you will find discussions.

Me, I'd replace the screws for the thin metal diaphragm with Allens. Much less swearing all around.

If the steel diaphragm isn't dimpled or otherwise distorted where the spring loaded piece contacts it, there isn't really anything which needs to be replaced. Crush washers usually can re reused several times, and hardware doesn't usually go bad. Flushing the filter screen just requires the obvious disassembly and back and forth blowing of solvent.