T34-1966 Reservoir to Master Cylinder Tubing

[OKType3Tim]

I've been working to recreate the tubing that runs from the brake fluid reservoir to the master cylinder. (One step in the front end overhaul that Miss Molly is going through.)

I have the correct original reservoir. And purchased a new incorrect reservoir just so I could get a new rubber bushing, retainer, and exit pipe. The exit pipe is 5mm OD. My initial path has been to utilize 5mm copper tube to reproduce the tubing, since that would allow me to use "Green Hose" to make the connection between the exit pipe and the tubing down to the master cylinder.

I know!! That isn't the way the original was. Original uses a conversion hose to get from the reservoir to the tube (113.611.815) which is not readily available. And a 6mm OD line (343.611.805B) to get on down to the firewall area.

Through trial and error, I think I have arrived at a (possibly) correct bending pattern for the tubing. The majority of the tubing run will install in a horizontal position.

I've set up a test on the bench:

I get a steady dripping flow, but not a steady stream flow.

I can certainly move up to a 6 mm OD tube, but then have to solve the reservoir to tube connection issue.

Opinions/Advice?
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[raygreenwood]

Whatever rubber you use...needs to be EPDM....ONLY. The ID of whatever tubing or tube you use needs to be very close to the original tubing ID. Outside of those issues.....anything will work. I plan to use nylon on my 412. Ray

[pedro sainz]

[Bobnotch]

[OKType3Tim]

So, to further explain:

First, here is what I have so far at the master cylinder:

I think I have the 90* on the front that BobNotch mentioned.

The original reservoir location and tube path:

with the tubing that I've bent fitting like this:

I can refine the bending of the tubing some, to minimize the height of the "trap" that Pedro mentioned. But, the original design/installation seems to have this "trap". They put the hole low, but you still have to come back up over the beam. In other words, the bottom of the reservoir must be higher than any other point on the tubing run.

Question that I'm still concerned about is: Is the 5mm tube that I currently have bent going to provide sufficient flow; or do I need to move up to 6mm?
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[pedro sainz]

[OKType3Tim]

Ah, here is a possible answer. Thom has a setup similar to mine. Although he has a slight relocation of the reservoir to accommodate the different style reservoir that has the molded plastic tube coming out the bottom. He is using green hose, so his hard line has to be 5mm. (You can't get green hose to fit on 6mm tube.)

and when you come up from the hole through the chassis you have to clear the spare tire well.

Also: No, I haven't lowered the car.

Thanks for the feedback and suggestions. (But don't stop if there are more.)
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[pedro sainz]

[mjrpoulton]

Here are some images from when I recommissioned a September 1965 RHD T34 using a dual circuit cylinder and reservoir to replace the original single circuit items.

The original reservoir was mounted higher up than yours.

I fitted the dual circuit a bit lower to enable it to be accessed easier. Yes the spare wheel cover still fits.

The pipework ran through a grommet in the tank support cross member and the spare wheel well has a cut out in the edge to allow the pipe(s) to pass through.

From memory I think I used 5 mm outlet pipes on the reservoir sleeved up to 6mm before the flexible pipes to the cylinder, but at all times I managed to keep a gentle fall on the pipe run. I opened up the hole and used a larger grommet which has two holes for the pipes - did not need to amend the cutout in the spare wheel well. the well still bolts back in, just a bit more of a wriggle!

Perhaps the 66on model year cars had the higher position reservoir and access hole in line with the tab on the inner wing from standard? Certainly makes it easier to get the fall you need, but in the original position was virtually impossible to see the level let alone refill by conventional means - hence all the dissolved paint!

[Nate M.]

If the bottom of the reservoir is higher than the top of the MC, flow will not be an issue once it's bled. That said, I would invest in a pressure bleeder and this all will be a moot point.
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Regards,

Nate M.

Squarsche build
Heavy Metal Affliction feature

For heaven's sake, put a type4 and a Porsche 5-speed in there. . . It's the right thing to do!!

[Bobnotch]

On my own 64 T-34, I added an extra hole for the 2nd blue hose. I also used a late model T-3 res jug, but kept it in the original position. What I did was add a spacer and longer screw to hold the jug in place. By going with late model jug and dual master cylinder, I just hosed it in with blue hose from end to end, and I eliminated any possible locations for leaks (no splices).

I don't know why VW or Karmann located the res jug so low up front though. I mean on a Notch or Square of the same vintage it's located a couple of inches higher up for better flow to the master cylinder. And if you look at the later type 3s, it's located even higher.

Tim, I see you do have the correct front plastic fitting. I think it was the angle of your 1st two photos that made me ask/question whether or not you had it.
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120

[OKType3Tim]

Ok, Done!

Only item left, is to fit the newer (larger) Master Cylinder Cover Plate that is used for a dual circuit master cylinder. (this from any '67 or newer Type 3.

Here are the details:
Once I found Thom's picture, I realized that my concern about fluid flow had to be based in something I was doing wrong. Thom clearly has small diameter tube. I was trying to be precise by sourcing the 5mm copper tubing. I backed up on my thinking and went and got a piece of 4.8mm (3/16") coated steel tubing at the local APS. I refined my tubing bend pattern, bent a sample, and tested on the bench. Now I had free flow. Soft copper 5mm tube has an ID of .115 thousandths. The steel 4.8mm steel tube has an ID of .113 thousandths. The only thing it could be is that the soft copper was to easily crushed in the bending process. If any single bend crushed just ever so much, then that created a flow restriction.

Starting at the reservoir:
The correct reservoir is 131.611.301, of which I have a good version. I purchased a 113.611.301G which provided a new lid, a new bushing, new bushing nut, and a new 5mm Hard copper down pipe. Green hose is correct for 5mm tube and is working (not leaking) on the 4.8mm steel line.

(This picture helps you get oriented to where they placed the reservoir on the '66. The original reservoir allows the fill cap to be oriented away from the wiring harness, and the exit in the center points straight down toward the bulkhead hole.

IPSWest had the correct grommet for the tube passing through the bulkhead. The parts book only calls for one, and I've got it placed on the forward side of the bulkhead.

But might not hurt to put one on the backside also.

Regarding the tube bend pattern (with apologies to Pedro): The tube pattern produces a horizontal run, all of which is lower than the bottom of the reservoir. The bends needed to make it through the bulkhead do indeed create a trap; but as long as all sections of the tube are lower than the bottom of the reservoir, the brake fluid will flow.

The installation of the tube is really quite simple:

When it falls into place, it is cradled on the top of the beam bushing, between the body component and the beam mount. There is no metal to metal contact between the tube and either the body or beam mount. I suppose that I could go back and slip a split piece of green hose over the tube at this point.

The tab holds the tube very securely, no wiggle.

The end of the tube runs downhill to meet up with the hose assembly coming up from the master cylinder.

Everything is clearing everything. And there is a lot of everything in this area.

The details of the plumbing I used for the dual master cylinder arrangement in this picture. Note that "Blue Hose" has a good interference fit to the 1/4" fittings. But it is not good enough for a seal. The clamps are a requirement for this assemlby.

All 4 corners have rebuilt brake components. The calipers are rebuilt ATE units using great information from Ray Greenwood's post on the subject. Standard new parts on the rear brakes. The only components not replaced are: the long brake line tubing down the length of the pan, and the two metal lines from the split at the rear that head out to the hoses that feed each of the rear drums. The system was bled per regular procedure with the only difference being that I used the "Speed-Bleeders" that Ray recommended.

Thank you for the input, suggestions, cautions. I have a drawing of the tube bending pattern in PDF form if anyone ever needs it. PM me to request a copy. As always, comments/polite debate welcome.

Tim
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[raygreenwood]

Very nice!.....those speed bleeders are the bomb aren't they?
Ray

[OKType3Tim]

[OKType3Tim]

To finish up; a couple pictures and the drawing:

_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[raygreenwood]

Fantastic work!

I have one suggeation for you.

The white plastic barbed fittings between your hose sections....I would recommend a better quality of fitting. Those fittings with the flat flange are usually not known for their longevity with chemicals and wide ranges of temperature.

How about some fittings made of the same material as the fittings that push into the MC grommet?

At minimum the elbows at the MC are nylon. The best would be polypropylene .

On this page in McMaster Carr....scroll down to the polypropylene fittings

https://www.mcmaster.com/#standard-barbed-tube-fittings/=17o772w

Ray

[OKType3Tim]

[Bobnotch]

[OKType3Tim]

After many months, and several diversions; back on track for the T34.
To follow up on Ray's suggestion; the fittings were not suitable for the application, and they did weep some fluid. So I rebuilt the tubing/plumbing using the following components from McMaster-Carr: "5121K261" and "5341K139"

The result:

_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34