Remote Vacuum Servo

[MiamiSprite]

I purchased a powertune remote vacuum servo unit for single line braking systems for my 62 Sprite (948) with disc brakes at front. Brakes work well but want to give my left leg a break.

I was planning on installing it this weekend and figured I'd read the instructions. First thing I noticed is that the two brakes lines supplied ARE DIFFERENT:

Short Line: 3/8"x24UNF Nut with DIN Flare, both ends
Long Line: 10mmx1 Metric Nut with Bubble Flare, both ends

Instrcution show one line from brake M/C to Servo and one from Servo to 3-Way adapter. Unfortunately it does not specify which line to use where.

Assuming the lines supplied are correct, then I'm expecting that when I disconnect the (existing) line from the M/C to the 3-Way adapter that one end will be 3/8" (3-Way?) and the other 10mm (M/C?). Or the lines supplied are wrong. My fear is with crossthreading the Servo (since I will know the threads for the M/C and 3-Way when I remove the existing line).

Anyone have experience with this?

Thanks!

Carlos

 

[Trevor Jessie]

What are the threads on the unit itself? The threads on the T and MC are 3/8-24 and use bubble flares.

 

[racingenglishcars]

Is this what you have?

Short Line: 3/8"x24UNF Nut with DIN Flare, both ends
https://www.holden.co.uk/displayproduct.asp?pCode=065.645

Long Line: 10mmx1 Metric Nut with Bubble Flare, both ends
https://www.motorsport-tools.com/hose-fitting-female-nut-m10-x-1-p-246704.html

 

[MiamiSprite]

Trevor: That is sort of my problem, I realy can't get the gage in to see if the threads match the 24 TPI or 1.0 metric.

Don: The first are female and the lines have male nuts.

 

[rkep01]

Trevor: That is sort of my problem, I realy can't get the gage in to see if the threads match the 24 TPI or 1.0 metric.

Buy 2 bolts from a hardware store the size and thread that you need, and use them as your thread gauges. :thumbsup:

 

[Roger]

I think you should stop immediately!

LEFT leg?

 

[dklawson]

I think you should stop immediately!
LEFT leg?

I noticed the "left leg" comment as well. Right = Brake & Accelerator.

As above, buy a clean 3/8-24 bolt to check the threads in the fittings. You are not likely to find an M10x1 bolt a hardware store. However, 10mm is so much larger than the 3/8" that the bolt will be VERY loose in a hole tapped M10x1.

Also as stated above, you are likely to find all the brake line threads on your car are 3/8". I know that on later Minis they started introducing some of the M10 fittings.

If you have to source adapters or different brake lines I believe Summit Racing carried some of those components in M10.

 

[MiamiSprite]

Thanks to all. Will do as suggested and try the 3/8-24 bolt. I was surprised that they inlcuded the line with metric fittings. And yes, the minis have mixed fittings (found this on my 80 mini).

I will likely end up making new lines using copper/nickel pipes and my new flaring tool (K Tool 70081 - Brake Pipe Flaring Tool Kit).

Thanks Again to all. It's great to be able to get input from others.

Carlos

p.s.guess now I'll be refered to as Mr. 2-Right Legs :lol:

 

[MiamiSprite]

Found this very helpful:

https://www.fedhillusa.com/webnuts/common%20flares6.pdf

Carlos

 

[MiamiSprite]

Have been working on my mini so I have not made much progress on this. I did decided to remove the blower/fan to make room for the Servo. But before installing, I'll touch up the paint. Hope to post some pictures soon.

 

[SilentUnicorn]

Found this very helpful:

https://www.fedhillusa.com/webnuts/common%20flares6.pdf

Carlos

Very Nice chart! added to the library.


thanx
m

 

[JohnDough]

What size is your master cylinder's brake diameter? I'm asking as I have changed mine to a 3/4" with my disk brake change and never really felt the need for the servo. On another car I've driven the m/c was left at 7/8 and with disk brakes in front you really need have a firm right foot.

I guess I'm trying to say I would rather get the hydraulics right on a car this light before adding complexity of a servo with added failure points.

 

[MiamiSprite]

The P/O repalced drums with disc up front but kept the 7/8 m/c. I suspect if I would have gone to a 3/4 m/c it would have fixed the problem. At the time I could not find a 3/4 m/c and did not want to send out to re-sleeve. Now I see that MOSS came out with a 3/4 m/c.

I finally got to it last Thursday and installed the brake booster. I started working on it at ~ 10 am and was done by 5 pm (lots of breaks, very hot day). It was not as difficult as I figured. The most difficult part was removing the carbs and manifold to drill and tap vacuum connection and figuring out where and how to mount. The latter was difficult only becuase I decided that no holes would be drilled (leaving me to use existing holes) so I could reverse with no need to weld holes shut.

Turns out that one of the lines (Long Line) suplied with the kit (with metric flares) was wrong. No problem because I only needed one line and made my own.

Now I have brakes. Made a huge difference. The car is much funner to drive.

Now I'm wondering how much better it would be if I replace the 7/8 m/c with a 3/4 m/c.

[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_006.jpg[image]
[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_001.jpg[image]
[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_002.jpg[image]
[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_003.jpg[image]
[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_004.jpg[image]
[image]https://i1258.photobucket.com/albums/ii531/hernaci/Sprite1/Brake_Booster_005.jpg[image]
OK - still having trouble with images.

 

[bthompson]

Here ya go! You just needed to close with a [/image] at the end of the URL instead of an [image].
MiamiSprite's images:

 

[MiamiSprite]

Man I spent hours trying to figure out what was wrong - Thanks////////////!