[Rovernet] Reflections on the need for more cans (was NADA 3500S Servo)

Fri Jan 10 12:52:07 EST 2014

Kent, Ben, Lou, et al...

I feel the need to jump in and share what I 'think' that I know about these
braking systems.  The Dunlop system was used only through '66 then the rest
of the production run, for the NADA cars at least, are Lockheed.  My '67 and
'69 TCs and '70 3500S are Lockheed.  

Agreeing with Ben here... my 3500S never had the wonderful brake feel of my
TCs.  They were sluggish to apply and release but compensated by showing
complete indifference to my attempts to modulate pressures.  I never
understood why anyone thought that modulating the vacuum pressures at the
master cylinder was an effective way to control the hydraulic pressures.
After studying the 3500S brakes for a couple of years I decided there was no
way to fix this hopelessly poor design and it ditched everything between the
brake pedal and the output of the vacuum servos.  On a trip to London I
bought a European master cylinder and single vacuum servo, probably the
8"... I'd go outside and measure it but it's raining and 33degF... and
installed that.  Now the brakes were much better although still a bit
sluggish but much better.  What I gave up was the dual circuit capability
and haven't missed it.  (Your lawyer may be grabbing for his heart at the
last statement but given more time and money one could come up with a good
feeling dual circuit restoration.)

As an aside if one were to wish for even better brakes on a TC the front
discs and calipers from a 3500S will swap seamlessly.  The three-piston
calipers are much easier to modulate and more powerful than the
single-piston calipers.  My '67 is thusly equipped and is wonderfully
responsive in braking.  I have another 3500S caliper/disc set waiting for my
'69 TC to become operational. 

Yes, I'm certain that some are aghast at the irreverence of someone changing
what the factory pushed out the door way back when.  I'm not.  Anyone having
been part of designing things in the real world will understand the
statement that the designers and engineers don't work for The Almighty they
work for the lawyers, account managers and project managers of their
company.  Designers and engineers are only very rarely told to go forth and
do the best you can and take as long as you want.  They are told to go
forth, do the best you can and we can afford 20 man hours for you to fix
that problem.  You do what you can in the allowed time, throw the result
over the transom and wait for the next assignment. So just because the
factory made it that way doesn't mean, to me, that's the way we have to keep
it.  For those who want their cars as original as possible you have my
blessing and heartfelt encouragement... but don't be surprised when I out
brake you going into turn one.  

Happy Rovering... and can we have some warm weather, Please. 
Gross

-----Original Message-----
From: Rovernet [mailto:rovernet-bounces at rovernet.org] On Behalf Of Ben
Saunders
Sent: Friday, January 10, 2014 9:40 AM
To: 'Rovernet'
Subject: Re: [Rovernet] Reflections on the need for more cans (was NADA
3500S Servo)

Hi Kent,
This reminds me more of "Stop in the name of love".

Sorry to hear that you have been down and hope you are back in action soon
but do take it easy and give yourself a chance to fully recover. 

As for the 7" v s 8"cans I looked at using the 7" first but then discovered
that the left inner fender on 3500S was built with the holes to mount the 8"
booster on that side as well. The 8" for the 3500S has the studs on the
opposite side from the 7" booster and should bolt right up with little or no
alterations necessary. I have seen where the 8" booster is used on the right
in the UK with the same style cylinder as the 2000 on the single line brake
system. All I want to do is duplicate the 2000 TC system but with 8"
boosters to try to get rid of the long air/vacuum travel time that I feel is
at the bottom of the response problem. There are some magazine articles I
have read on the 3500S from the UK of test results on the car new that
remarks on the poor response of the brakes both in applying them and
releasing them. Like I said this is a design problem and I do remember that
I was quite impressed in the 2000 TC's stopping capability over the 3500S
some years back when I had both. At the present time I am using the 2000
7"style remote booster on my 1960 P4 100 in place of the original and it
works well. I also used the same on the P3 but have yet to road test it to
see how it preforms. I may have to go up on the cylinder size on that one.
Now that I think of it I might want to go to the 8" boosters for both of
them as well although I will have to watch out for over braking the P3 with
its' narrow tires. 
Cheers,
Ben

-----Original Message-----
From: Rovernet [mailto:rovernet-bounces at rovernet.org] On Behalf Of Kent
Kinard
Sent: Thursday, January 09, 2014 10:15 PM
To: Rovernet
Subject: [Rovernet] Reflections on the need for more cans (was NADA 3500S
Servo)

How many cans must one man have, before they can call him a man?
And how many seas must a white Rover sail, before she sleeps in the sand?
Is that a song? Should be.

Why not use the 7" cans if you are using two? Easier to fit. I can do sevens
all day. Or did I can all my sevens? Actually, two sevens can't, I guess.
Wrong boost ratio?

I have 8's, but if Geff has one laying on the shelf ready to go, that's a
better deal as far as I'm concerned. I just spent three days in the
hospital. Went to the shop and tried to do too much today. Landed on my can.

Roverhallucinogenicly (too much morphine or not enough, Geff would know. 
Actually, I never got a buzz, so I must have really been hurting.) Kent K.

GeffMcCarthy wrote:
> Think I have a spare can, if Kent cannot find one.
>
> AvMedSafe
> Geoffrey W. McCarthy MD MBA DipAvMed
> 677 NW Melinda Ave Portland OR USA 97210
> 503-241-8468(h) 503-799-3809 (mobile)
>
> -----Original Message-----
> From: Rovernet [mailto:rovernet-bounces at rovernet.org] On Behalf Of 
> Kent Kinard
> Sent: Thursday, January 09, 2014 7:30 AM
> To: Rovernet
> Subject: Re: [Rovernet] NADA 3500S Servo
>
> Hi Ben,
> I have some. How fast do you need one as I may have to pull one from a
car.
> Kent K.
>
> Ben Saunders wrote:
>> Hello Rovernetters,
>> I am looking for a 1970 Rover 3500S NADA vacuum servo. All I need is 
>> the can and not the cylinder.
>> Thanks,
>> Ben
>>
>> Ben & Cathy Saunders
>> P O Box 846
>> Columbia, Va. 23038
>> (434) 842-3667
>>
>>
>> _______________________________________________
>> Rovernet mailing list
>> Rovernet at rovernet.org
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>>
>
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