TheSamba.com :: View topic - Can an average joe re-bush a Solex 34pict3 carb

Sat Sep 03, 2016 1:01 am

Well, here I go again. Those of you who've seen my "average joe" heater channel thread http://www.thesamba.com/vw/forum/viewtopic.php?t=598829 will know what I'm talking about.

My next "average joe" experiment was going to be about converting from an 009 distributor to SVDA http://www.thesamba.com/vw/forum/viewtopic.php?t=662300 but it's on hold because I've discovered that my leaky carb may need to be addressed first.

I realize there are carb rebuild kits that essentially involve replacing some gaskets and other basic parts, but my problem is that the throttle shaft is leaking and needs to be rebushed. I've found there to be some spotty info about this fix so I'm gonna try to document my experiment again for all you average joes out there like me.

I've never done this before and I'm not trained on these matters so use your own discernment whether you want to do as I do! I know a carb is a very complicated and finicky piece of engineering so I'm not pretending to know what I'm doing. If I were smart like the rest of you, I'd send this out to a professional, but my lot in life is to do things the hard way.

First of all, here's my problem... fuel leaking from the throttle shaft. Note the grime around it...

On the other side too. All over really. I don't have that fancy fire extinguisher you put in the engine bay, so I'm gonna play it safe and fix this thing...

Step 1: Remove carb.
Here it is off the engine. You'll figure it out. Remove a couple nuts from the bottom of the carb and a couple wires on the sides. And remember to pour the fuel out into a gas can before you spill it all over your pants...

Step 2: Disconnect accelerator pump connecting link.
I'm starting here because my primary focus is on the throttle shaft bushing. And this step will allow you to work on the throttle plate without it trying to spring closed. Just pull the pin. Here it is after disconnecting...

Btw, I know what these parts are called because of this great webpage http://www.vw-resource.com/carb_41.html All the part names I'll be using will come from this resource.

Step 3: Remove 2 screws on the throttle plate.
This could end up quite the chore because the screws are peened on the back...

I guess some folks use a Dremel to remove the peening but I didn't have one. I tried using a half round file but that quickly turned tedious and unfun, so I inspected the screws closely and it really didn't look like it'd be hard to unscrew...

Lucky for me, which is rare, it did in fact turn out to be relatively easy to unscrew, but it's very important to have a screwdriver bit that fits well to avoid stripping the head since the screw is pretty soft...

There was nearly no damage to the screw and the shaft but YMMV. I hope to reuse the screws.

Step 4: Remove throttle plate.
Just slip it out but remember the orientation for reassembly!

Step 5: Remove upper cover.
I found it helpful to do this now so it's easier to work with. Just remove the 5 screws on top and you end up with this. Oh, and pull out that injector, the thing above the bowl that looks like a tiny kitchen faucet from your daughter's dollhouse. That's a fragile piece you don't want to break while wrenching on other parts. Remove the float and retainer too...

Step 6: Remove the cutoff valve
This is needed to make room for the throttle shaft to come out...

Step 7: Remove nut on the throttle shaft.
This part can feel a little awkward. If you're too rough, I think you could damage the shaft. I found it safest to turn the carb upside down and let the "fast idle lever" (on the left in this photo) rest on the body as you're unscrewing the nut (on the right). The other thing I did was use a big box wrench to hold the "adjustable bell crank". All this to make sure I don't torque something off while I'm unscrewing. Just required a firm turn, don't be scared...

And you end up with this...

Here's the culprit for the leaks, the bushings. I don't know if they are original, but they are plastic and actually look pretty new...

But they look too big. Look closely head on and you'll see some gap that fuel can leak through. I'm guessing a PO made a good but insufficient attempt at this...

So now I think the hardest part of this job is going to be sourcing quality brass bushings or bearings to replace this. For some reason, you can't just buy them at our friendly Type 1 retailers. But now with the actual throttle shaft and carb body in hand, I'm going shopping.

Sat Sep 03, 2016 1:32 am

We found a pretty good fit at the hobby store for RC airplanes---and another source is old telescoping radio antenna- with chrom - they may be a bit bigger.

Sat Sep 03, 2016 4:49 am

I've heard a valve guide can be cut down and used but never tired it. We had a rebushing kit back in the day that came with the bushings.

Sat Sep 03, 2016 5:19 pm

Called a bunch of flaps, hobby stores and a couple ACVW shops. No luck. The ACVW shops said to just buy a new carb and recommended against using a valve guide or other such antics.

Then I went to the local Ace, which I love btw for other purposes, and found this in the hobby section...

How tight does the fit need to be? The shaft fits in the bushing with a tiny bit of slop. The gap is maybe one layer of aluminum foil...

The bushing fits in the carb less well but only slightly...

I'm guessing the fit needs to be really snug, yes? If so I'll probably check out a Graingers or a local fittings shop.

Sat Sep 03, 2016 6:23 pm

Snug, yes, no air leaks.

Sat Sep 03, 2016 7:59 pm

:lol: You may get some thermal expansion- so a little bit of play may be a benefit. - no shims round the shaft.

my expirence with bushing is -you are really sealing air out more than gas in- you will see gas on any carb when it is flooding and pissing down the intake.

Some other observations-- your accelerator nozzle should put its spray into the carb -pointing at the earliest opening of the the throttle butterfly-

For some reason VW only seals one galley at the mounting flange - I like to pinch off a small piece of solder and flatten it into the the ones that are left open.

I like your "how to" articles" keep up the good work-

Sat Sep 03, 2016 10:10 pm

So 1 vote for "snug" and 1 vote for "little bit of play". Who wants to be the tie breaker?!

Btw I looked up "thermal expansion" and brass expands more than carbon steel but I assume the carb itself doesn't get as hot as the case... so I guess that favors the "snug" camp :)

Sun Sep 04, 2016 4:00 am

I think it admirable that you would attemp this. Might i suggest that instead of using whatever tube stock you can find that you seek a machinist with a lathe. You then coud specify the required bush dimension with a tolerence. Brass rod is easy to find and turning it on a lathe is one of the easiest metals to shape because of its softness. So it wouldn't be costly to do but allows more precise fitting.

Nicholas

Sun Sep 04, 2016 6:57 am

I bought mine on Ebay from a guy who machined them. They were from Great Britain. He is no longer listing them but there are other sellers. Not sure if they are as good.

Sun Sep 04, 2016 8:12 am

sputnick60 wrote: I think it admirable that you would attemp this. Might i suggest that instead of using whatever tube stock you can find that you seek a machinist with a lathe.

Admirable? No, I'm just a cheapskate!

Even if I had a machinist do it, I still don't know how tight they would have to make it. Would still appreciate more input on snug vs play.

Sun Sep 04, 2016 9:12 am

:lol: Not being there to determine "snug" from loose - I can only recommend- putting it all together and see if its better.- A loose bushing in a hole can be firmed up with many products from "jell seal" to JB weld. (if using any product like that --assemble with the shaft installed as mis alignment can be fatal)- Then "thick marine grease" vrs "Lubriplate" can be used on the assembly.

as far as building a new shaft goes- I would guess slicing a new groove for a throttle plate thru a brass rod might prove past my skill level.

If you get stuck- PM me about my pile of cores.

Tue Sep 06, 2016 11:36 am

Blue_Ghia wrote: I bought mine on Ebay from a guy who machined them. They were from Great Britain. He is no longer listing them but there are other sellers. Not sure if they are as good.

Likewise I decided to go the eBay route. Currently there is a seller "motorsport-parts-08" in the UK (Ockenden Engineering) and it cost me US $15.75 shipped for the pair. Let's see how long it takes to get here to the US.

My throttle shaft and body do not seem very worn and this seller claims a precision fit specifically for these solexes so I figured that was a better bet than someone like me trying to source something from scratch. Will update how these work. They said they have many available in case anyone else is interested.

Tue Sep 06, 2016 1:02 pm

Hi J1, living in UK Ive had a few sets of bushes from for that seller and found them to be just the job and have cured my leaking spindles. Don't forget to clean the spindle before you replace it or you will find it sticking. Unfortunately I need bushes for an old 1200cc engine with a Solex 28 PCI carburetor and he can't supply :( . Anyone your side of the big pond can help me.
Robert

Tue Sep 06, 2016 2:09 pm

c705ncp wrote: Hi J1, living in UK Ive had a few sets of bushes from for that seller and found them to be just the job and have cured my leaking spindles.

Great! So encouraging to hear that as I look out the window anticipating the delivery truck. I'm sure many of you can relate to the frustration of being off the road because of a small piece of metal.

Tue Sep 06, 2016 2:26 pm

Since putting reply on forum have been in touch with a guy in Germany who tells me that Solex 28 PCI carb does not have bushes and will have to find bushes to fit spindle and drill carb to fit bushes. :idea: Nothing easy with old VW's but we all like them :lol: Have a look at my blog about 'sleeping pod' and you will picture of my 73 Ghia
Robert

Wed Sep 07, 2016 6:26 am

If you have a 9mm valve guide reamer- you may get a nice new surface to work with and then cut your brass on a lathe to fit.

:lol: let us know if this works??

Wed Sep 14, 2016 10:14 pm

The bushings originating in the UK arrived in California in 8 days from ordering. Not bad at all.

This is a pencil for reference...

The outer diameter is a tad too big for the carb body...

And the inner diameter is a tad too small for the throttle shaft...

I think I'll be lightly sanding both the inside and outside of the bushing, as opposed to altering the shaft or carb body.

The rebushing kit arrived as well so all I need is a little bit of time!

Fri Sep 16, 2016 11:24 pm

So now...

Step 8: Sand new throttle shaft bushings to fit

My poor man's way of sanding down the bushing. For the inner diameter, sandpaper taped to a pencil that is in a hand drill. A standard pencil is a nice fit. For the outer diameter...

Btw the length seems to be a perfect fit so no need to mess with that. Fits very snugly in the carb...

And test fitting the throttle shaft...

Question: I'm guessing I'm overthinking this but the shaft is rotating in the bushing as opposed to the bushing rotating in the carb body. In other words the outer diameter of the bushing fits tighter than the inner diameter. Is that how it should work?

Sat Sep 17, 2016 6:15 am

J1 wrote:
Question: I'm guessing I'm overthinking this but the shaft is rotating in the bushing as opposed to the bushing rotating in the carb body. In other words the outer diameter of the bushing fits tighter than the inner diameter. Is that how it should work?

YES! you want the bushing to wear on the inside(shaft side) - not have the carb body wear outside of the bushing.

Sat Sep 17, 2016 9:09 am

:lol: Nice work around- good job-