W123 brake booster check valve - replacement unavailable?
 

Hello, I have a 1983 300d with a broken check valve on the main vac line running from the vac pump to the booster.

Unfortunately, the replacement part #1234307429 doesn't seem to be available anywhere anymore. I ordered it from Pelican Parts but the order was cancelled because their supplier no longer makes it.

My understanding is that the check valve can't be purchased on its own. I have already used epoxy to repair the broken nipple on the valve once, but it didn't last and the nature of the break makes a permanent repair very difficult.

Has anyone had any luck fabricating a replacement? It seems like it would be possible to pull the check valve out, replace with a generic check valve and then add a tee in the line to feed the rest of the vacuum system. Does anyone here have thoughts? Thank you.

When I made less money and had more time, I'd be inclined to farmer up a fix. At this point the whole hose at $42 isn't expensive compared to a few hours messing around with no good result or sleeping easy on a brake repair.

https://www.pelicanparts.com/More_Info/1234307429.htm?pn=123-430-74-29-INT&SVSVSI=3389&fs=0

Thanks for the link - unfortunately, that hose is not actually available from Pelican Parts, as I learned after I ordered it and then had the ordered cancelled because their supplier no longer makes it. I have been unable to find the hose in stock anywhere, hence my predicament.

Agree with "moon" 100%. Dont waste your time only to end up with a substandard repair/part. Although it "looks" like you should be able to pull the old one out and slide in a new one, these lines dont work like that. Not that flexible. Similar connections on the fuel systems and MB def doesnt want them coming apart. Dont risk your brakes/vacuum system for 42 bones. One less thing to worry about and you'll know it's "right".

I would happily pay for the hose 123boy, but I can't actually find it in stock. It sounds like, after talking to Pelican Parts on the phone, Cohline isn't making the part anymore.

If anyone finds a link where it's in stock or has one they'd like to sell please do let me know! Unfortunately I live way out in rural Maine far from any MB junkyards and I can't seem to find the part on eBay, so I'm looking at fabricating something unless I can order the hose somewhere...

https://www.*******.com/products/mercedes-power-brake-booster-line-300d-300td-genuine-mercedes-mer-1244301229\\]

sorry, this is for an 87.

Try the classic center, or find a junkyard at car-part.com and have them ship the part.

Appreciate your help - yeah, the 1987 looks quite similar but apparently it doesn't fit.

I have a few calls out to junkyards listed on car-parts.com so I guess I'll see what happens. So frustrating that the main feed to the entire vacuum system is so fragile!

Sorry, my mistake. Thought you looking for the hose only, without the check valve, to do your own repair.
Sorry I cant be of more help. Nothing worse than important parts for our cherished old cars becoming NLA.....

If you wanted to construct a new line with rubber vacuum hose you need to save the end fittings and nuts. Check valves can be had as in the attached picture or they have plastic ones. EBay and Amazon sell them.

You will have to find something that works for the little nipples to T into the main line. It could be done with Brass fittings.

I replaced the plastic tubing on my Power Brake Booster Vacuum Line with rubber vacuum hose. I increased the length so I could run the line over the top of the fender well were it was less likely to be damaged.

That's odd, I got one off pelican a few months ago. Are you sure it's unavailable? You've also tried ebay?

Make sure you save the old flare fittings.
For whatever reason, the fittings of the new hose -at least for my car- made some odd angles that left me unable to install it without a little surgery.
The hose can be manipulated with a heat gun but you have to be fast and precise.
I cut the old line up and practiced a few times.


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Shern - It appears that Pelican Parts just ran out of stock and the supplier no longer makes it. If you go to PP it will allow you to add the item to your cart, but your order will be cancelled - I spoke to someone at the parts warehouse and they said it's no longer available. I've been checking ebay but nothing has popped up.

Not having a lot of luck with junk yards, many places refuse to do anything with brake or vacuum lines 🤷

Diesel 911- thanks for the tip. I may end up doing that. I wonder if anyone knows the pressure differential spec for the check valve - or is it pretty standard? Something like this seems like it might work - Aluminum One-Way Check Valve 12mm Barbed - it says it holds 90 PSI.

I just called the dealer and they told me NLA, but they did sell it not too long ago for $26.

That really sucks.

This sounds like great advice and a good solution. The phrase "necessity is the mother of invention" comes to mind. Really does suck when these parts just go "NLA" with no warning or recourse.
I, too, just bought one for my 83 240D from PP "not too long ago", as well.
I was recently looking for an ac line for my 97 E300D, guess what? NLA. It's the main low pressure line from the compressor to evaporator with the "low side" charge port in the middle. I found one on eBay from Germany, for $20!!!, but the guy wouldn't ship to the U.S. The new part from MB was over $300. Not having much luck.
My local dealer kindly did a "national search" of all the MB dealers, hoping to locate the line in someones parts dept.(no bueno). I wondered if you could get a dealer to perform that same search for your brake booster line? Surely, there's gotta be a new (or used) one of those, somewhere on this planet, yes?
I know there are also a lot of members here who also stock up on old parts. Have you tried placing a request in the "wanted" section?

Where are you? I have several spares (Sacramento, CA). If pressed, you could custom plumb. Post 9 shows some parts. I recall seeing generic vac booster check valves in bubble packs at Autozone. Most are for the type which push into a rubber grommet on the booster, but might be some inline hose type. Also search on ebay and Amazon.

This from post #5...."Unfortunately I live way out in rural Maine far from any MB junkyards".
Surely this isn't an insurmountable problem. I understand wanting new, NOS or a good used part. But, certainly, something could be cobbled together with satisfactory results.
I'd like to hear how Diesel911's solution is working out and holding up.
I tried to PM the OP to suggest a few specific members that I've purchased used parts from in the past. PM'd mainly for discretion and not broadcasting the info "all over the internet". The "PM" feature of the OP's account is not turned on or enabled? So, who knows.....