Servo Hose Diameter?

[Tinster]

I received the new servo to manifold hose today
for my dead TR. (Yes, I have faith someday there
be moving engine parts to create a vacuum.)

The old hose is 6/16" inside diam. The new hose
is 5/16" and I cannot get it to fit over either
nipple. My metal file can easily reduce the nipple
sizes to 5/16" (ouch for sure!)

BUT is 5/16" inside hose diameter enough area (volume)
to adequately service the needs of the brake servo??

The 5/16" hose cross section reduction is about 20%,
the volume is reduced by 30%

Cool! That sounds very technical.... given I have
almost no idea what the servo unit actually does.

As always,

Thanks,

Tinster in Puerto Rico /ubbthreads/images/graemlins/rolleyes.gif /ubbthreads/images/graemlins/rolleyes.gif

 

[PeterK]

No, you should be using a 3/8" (6/16"!) vacuum hose (not gas line). It must be the correct diameter and must be vacuum hose so that it will not collapse. Ask at your auto parts store. Do they have NAPA in PR?

 

[Guest]

[ QUOTE ]
I received the new servo to manifold hose today
for my dead TR.

[/ QUOTE ]

It's not dead, it's just resting.


The diameter of the vacumn hose really isn't critical. Whatever fits over the plastic elbo fitting that snugs up into the brake servo. This is a plastic barbed fitting so you want whatever hose to fit tightly but not no tight that you have to jamb it on. Might want to look for true vacumn hose material (every auto shop sells it) because it has less tendancy to collapse under vacumn. The other end will fit onto the barbed end at the intake, might want a clamp here if it seems too loose. Most cars came with a stainless loop clamp that held the hose to the last bolt head on the valve cover. Interestingly, I can remove the vacumn hose from my servo a month after the car hasn't been run and I can still hear the "whoosh" of a vacumn release.
Do I have a tight head or what!



Bill

 

[Tinster]

Confusing to say the least.
I purchased said hose from Victoria British
as their servo hose replacement part.

I seems quite strong and reminds me of a steel
belted radial tire cross section. The outside is
covered with some very fine woven, cloth-like material.

D

 

[Brosky]

Dale you are correct. A "good quality" vacuum hose for that amount of pull or vacuum will be reinforced to prevent collapse, so you have the quality. I'm still waiting for TRF to send my new hose that I ordered several months ago, but the backorder continues, so I can't measure their version to compare. I would measure the sizes and get what will fit over the nipples correctly, both on the manifold and the booster.

The one thing that you do NOT want to break by forcing anything is the plastic nipple on the booster. I'm not sure if you can still buy them and if so, I think that someone said in a previous post that they cost about $50.00.

 

[Tinster]

Thanks All- I think I'd better take the hose
and drag it around town looking for a similar
material but in 3/8" inside diameter.

I have had many problems with Victoria British parts
but TRF seems to have very few parts in stock and then
months of " backordered " go by with no word from them.

So it's all a crap shoot.

d

 

[martx-5]

Well, there's also Moss Motors. Their backorder rate is almost non-existent on most items. I placed an order with them last week, and one item was back ordered. I just got an e-mail from them saying the back ordered item was shipped today.
/ubbthreads/images/graemlins/driving.gif

 

[RobT]

I believe 11/32 ID is in fact the correct size - but hard to find. 3/8 will work fine - only 1/32 larger. For tight fitting connections, a little lighter fluid on the hose will help it slip on.

Rob.