W123 Vacuum leak finding and Floor flap pod replacement

I guess I just gave away where the leak was! I've got some good tips for finding a vacuum leak on your classic Mercedes though, a simple process with inexpensive tools to narrow down what is causing your vacuum woes.
Here are the things you'll want to have on hand:
➡My Vacuum diagrams: trythistv.com/...
➡Mityvac MV8000 Silverline Vacuum pump: amzn.to/3BaVI1x
➡Options for a vacuum gauge if you would prefer a larger dial at the loss of being able to pump vacuum with your hands: amzn.to/3QsD3D3 or amzn.to/3Q9YwAh
➡Floor flap Vacuum pod part number is 123-800-31-75, Shop around on that one, Pelicanparts has decent prices usually, sometimes other places have better.
These links may be affiliate links, which earn me a commission if you choose to purchase from one.

[@trythistv]

Here are the things you'll want to have on hand: My Vacuum diagrams: trythistv.com/w123vacuum/ Mityvac MV8000 Silverline Vacuum pump: amzn.to/3BaVI1x Options for a vacuum gauge if you would prefer a larger dial at the loss of being able to pump vacuum with your hands: amzn.to/3QsD3D3 or amzn.to/3Q9YwAh Floor flap Vacuum pod part number is 123-800-31-75, Shop around on that one, Pelicanparts has decent prices usually, sometimes other places have better. These links may be affiliate links, which earn me a commission if you choose to purchase from one.

this is the best demo for replacing the floor flap pod.

[@chriscadman5715]

Great job! Thanks for showing me the detent on the bayonet mount.

[@trythistv]

Its miserable to try to get the pod out if you didn't see that!

[@larryhernandez3465]

Thanks for the consistent quality information and persistence efforts on your part, I have worked on my 83 w123 coupe for 7 years now and know how frustrating yet very satisfying it is when you resolve an issue. Keep that curiosity and positive energy you share with the world! "Live long and prosper" !

[@trythistv]

Thank you sir! It seems like a lot of vacuum pods are failing on me recently, so likely they will be for everyone else in the community too, and thankfully parts have seemed to become more plentiful recently, more aftermarket companies have started making parts, and competition there leads to better quality parts and better prices so we can keep our cars going for a long time!

[@thepreservationistne]

Solid video. Very helpful. May the KZbin monetary gods smile on you.

[@trythistv]

Indeed, I hope the same, however I refuse to turn on the ads that come on in the middle of the video because they irritate me lol, and KZbin constantly bugs me that I could earn more if I turn them on but I'm not doing it, I'd rather people be able to watch my whole videos without interruption!

[@karlwezmar]

Thanks so much. I have a 300CD 79 - new vacuum pump, so we we got that. Brakes super hard, and still an issue, so we gotta start there. HVAC is totally inoperative. I got a digital system which I'll document. She's only got 60K on her, so it's worth going all the away. 99% rust free - then once mechanically good to go, we go for the window-our restorations. (I need all the deals - hard to find). THANK YOU!!!!

[@trythistv]

60k! WOW! You'll have yourself a special car after you solve those little issues. Usually even good sized vacuum leaks from the hvac and lock systems that are super common won't make the brakes too hard, unless you've got a booster problem, but if you've got multiple leaks in multiple places it could. Hope to hear more about your journey getting it back roadworthy and the restoration process! I desperately need to paint my car, the sun down south has not been kind to the clearcoat.

[@blublaw]

Seriously one of the best channels for w123 work, I've fixed quite a few things on my car with your videos and am very grateful. Keep making 300D videos and we'll keep watching them! Do you have an updated vacuum system map by any chance? Thanks again

[@trythistv]

Thanks so much! The latest update on the diagrams I have is on the website (trythistv.com/w123vacuum/) December 2021 update was my latest, I believe I have it basically done as far as lines and what they go to, I don't have all the colors perfect yet, and I want to notate a few extra tidbits, but I think it should fairly well cover the cars I have access to examine (82 300d), if you, or anyone else notice anything I've missed, please tell me and I will see what I can research and come up with to correct it!

[@R8V8Vantage599]

Thank you for taking the time to explain this!!!

[@trythistv]

Glad it helped you out!

[@teesaeed6529]

Thansk a lot for such a detailed video.

[@trythistv]

I certainly try to make them as informative as possible. 😀

[@danpicocfp6276]

Keep good going!

[@daveyvane]

I have had many 123s and 126s. When activating CC buttons, I could distinctly hear a flap closing under the passenger upper dash. But only in the “perfect” car. Never hear it in any others.

[@trythistv]

That sounds like it was either the main air flap or the recirculate flap, and I do recall some cars making a very obvious flop sound while others don't seem to. I should really test mine, I did a video a while ago about a modification to enable 100% recirculation to help out the AC in hotter climates like where I'm at, I should verify the flaps are closing and sealing properly. Thanks a bunch for that thought, I'll check my flaps for proper function!

[@vintage76vipergreenBeetle]

Nice info.👍 I got one of your w123 t-shirt on order.

[@trythistv]

Very cool! I'm excited to hear what you think of it, Mine has to be one of the most comfortable shirts I own, I hope you love it!

[@vintage76vipergreenBeetle]

@@trythistv The vendor that sells the t-shirts has feedback,I'm not sure if its from your shirts, or all the shirts they sell? I'll leave you a comment when the shirt arrives. I regret not buying a w123 20+ years ago,when they had less rust and were cheaper to buy.😕 The w123 diesels are one of my favorite cars. I may have to sell my 1st car (76 vw bug) to get one.

[@trythistv]

I believe that feedback is just generic for their shirts, You're the first person to get one of my shirts other than myself! The w123s seem to fluctuate wildly in price, I've seen really rough examples listed for 5k or more, but my grey one I only paid $1300 for, and in some ways, I overpaid, there was a lot of hidden rust and issues that have been a pain to keep up with, but it is a fun car, I've 4 speed swapped it, done some other little stuff as well to make it cruise around nicely and keep up with traffic. My blue one was an even better deal initially, but had some severe mechanical issues, such as no oil pressure, oil leaking out about as fast as it went in, worn down cam lobes, damaged rockers, siezed up vacuum pump bearings, and such, but has been an absolute treat to drive after sorting out those issues, and has been an incredibly reliable car ever since, and as you can tell, I keep making improvements and it just keeps paying me back in year after year of basically problem free enjoyment.

[@vintage76vipergreenBeetle]

@@trythistv Check out marketplace in New England area, to see what w123 are going for.

[@trythistv]

OK Wow. Time for you to take a trip down south, The cars down here are cheaper and don't look half as rusty. Some decent cars around that need some paint, and mechanical repairs, but have good bones, which is way harder to find up north.

[@Us-two]

OK, so where did you find that ferret that is sitting on your head from half way through the video?

[@trythistv]

It kind of comes and goes as it pleases. Seems to be some kind of wild diagnostic ferret. Untamable. Not sure exactly how to deal with its erratic appearances.

[@ismailcigerli3456]

Hi I see a black line looks like a Vacuum line it’s hanging down between the brake pedal and gas pedal do you know where that connects to I have that as well hanging loose

[@trythistv]

I would bet that is the vent line for the transmission modulator. If it is, It tees off one side of the modulator and port 2 on the egr changeover valve. I would place it somewhere out of the way, out of sight is optional

[@robertciganovic965]

Very nice video

[@sonofprince4124]

What problem was the leak causing?

[@trythistv]

All kinds of vacuum related problems. Slow shutdown or no shutdown with key, door locks non functional, and of course all the HVAC controls did not change which vents air came out of. Basically everything on the branch of vacuum that has the HVAC on it stopped working. I didn't notice a difference in the brake booster function or transmission harshness but that is likely due to being on a different branch, and the brake booster getting the direct unrestricted feed.

[@sonofprince4124]

@@trythistv That is Awesome! When you say slow shutdown...You mean when turning key off it was taking long time to shut off the engine? Also can you give advice on removing a rear door regulator from salvage yard where there is no power to let the window down to unscrew the top of the regulator from the window frame? I was short on time and had to leave I didn't look up to see is it possible to remove the bolts with a fairly long extension but seem like I still want be able to fit the socket on the screw up there at that angle from below.

[@LiviuRo1]

My pod is working when suction is applied but is no vacuum in the red/yellow hose. Could be the climate button or the connector to it?

[@trythistv]

The vacuum valves behind the climate control buttons are electronic, one valve could have failed, the wire could have come disconnected, or the climate control button module thing could have a bad connection or failed component that is causing the valve to not receive a signal to open.

[@Random59427]

When my A/C is on, the driver, passenger, defrost, and footwell blows air, but the center vents do not. The air is not cold either.

[@trythistv]

Sounds like a vacuum leak for sure. I just had either another pod go bad or something, as my car stopped shutting off with the key when I have the HVAC in any position, so I'm going to have to hunt down whatever has given up. Guess 40 years of wear and tear on these vacuum pods takes its toll!

[@gbush1620]

Hi, my W210 has an issue of high-pitched noise while AC is on and here is the driving video. kzbin.info/www/bejne/mXLWoKZtpsmSbKc Do you think it is due to vaccum leaking due to actuator? Some user at Mercede Forum told me previously it is due to bad expansion valve. Thanks.

[@trythistv]

It is possible, The easy way to find out would be to disconnect and plug off the vacuum line for HVAC, on W123 it is green with a yellow stripe, not sure if W210 is the same, but if you plug that off it will default to defrost usually, so switch on your AC the same as always and see if the noise is still there, if it is gone, plug the vacuum line back in while the car is running, and see if the sound starts then. I'm not super familiar with the W210 body, but I know on my W123, all the AC modes open the center vents, and it could make a weird noise if it were leaking from that pod, but I'm no expert, worth checking out though!

[@tedx4263]

Journalism 101: When using acronyms like "HVAC" always identify what it stands for at least once. Also: Identify the parts by name or part number in case viewers need to replace them.

[@daveyvane]

Thank you Mrs Beasley. But these are at least 102 level. So HVAC usage is fine.