booster-less brake questions

[dtbaker61]

My SII does not have a vacuum brake booster, and that's fine... actually I don't WANT one because when I convert to electric I would have to add an electric vacuum pump if I had a booster....

What I am wondering is what is the difference between the older boosterless master cyl, and newer vehicles that all seem to have boosters? Do the boosterless masters have slightly smaller bores to raise the psi without requiring too much more travel? Is it just that the boosterless design requires a little more pedal pressure to stop the same?

In part I want to know because I suspect my master cyl on the SII is getting to the point of needing a rebuild, and the current remote reservoir line looks somewhat cobbled up although it is not leaking yet, the reservoir is a little rusty and nasty. The reservoir is stuck on a bracket right on the firewall next to the brace, but the feed line has a couple kinky looking 90 degree bends I don't like the look of.

I am wondering if there is a particular model of Wilwood or some other 'performance' master that might yield better braking while remaining boosterless?

or, would I have to also add in something like dual piston calipers in the front to get better braking with the same pedal pressure?

 

[RootesRacer]

Yes, boosterless takes a smaller master bore and more pedal travel to get the pressure and stroke needed.

The alpine is light enough that IMO the pedal effort is small and feedback is better without the booster anyhow.

BTW SII alpines didnt come with a booster anyway.

 

[65beam]

questions

series 2 cars used the master with a .700 bore and no booster. cars with a booster used a master with a .875 bore and a booster. i use the .700 on all of my alpines with no booster. a couple of my cars have the booster mounted with lines going in and out but the master section is welded up with the fluid passing thru on it's way to the brakes. i have no problems with this setup. the .700 master is easy to find. i buy them thru pegasus.

 

[RootesRacer]

series 2 cars used the master with a .700 bore and no booster. cars with a booster used a master with a .875 bore and a booster. i use the .700 on all of my alpines with no booster. a couple of my cars have the booster mounted with lines going in and out but the master section is welded up with the fluid passing thru on it's way to the brakes. i have no problems with this setup. the .700 master is easy to find. i buy them thru pegasus.

.700 are you sure? I thought that the SII was 5/8 (.625).

 

[dtbaker61]

this is precisely the info I need...
is the master bore .625?, and any ideas on what travel is needed? I know that stock replacements are available from a couple sources for the Alpine, but then I ALSO am interested in a similar unit for changing a Suzuki Swift to boosterless, but it has a different output setup with three lines out.

 

[65beam]

questions

i've used the .700 for probably 30 years so that is my choice. and they are easy to find. it's your choice what to use.

 

[dtbaker61]

i've used the .700 for probably 30 years so that is my choice. and they are easy to find. it's your choice what to use.

is this the one offered by Sunbeam Specialties? or, perhaps you could post ome of your other sources for them? I'll probably end up replacing rather than rebuilding the one in my SII....

then I'll look for a similar bore for the Suzuki to change IT to boosterless if I can find a suitable one.

 

[AlpineII]

Has anyone looked into one of these reverse type dual masters? Here are two types on e-bay: 120725622346 and 270564677336.

It would seem to resolve engine bay issues.

 

[65beam]

brakes

dan,
if you want a .700 master,call doug jennings in dayton ohio. i'm sure he has some in stock.

 

[gordonra]

Sunbeam Specialties has two masters listed:

0.710" bore for the Non-boosted earlier series and
0.875" bore for the later boosted series cars.

Just an additional note...

0.875" bore rear wheel cylinders were used on the non-boosted masters, while
0.75" bore rear wheel cylinders were used on the boosted masters.

As far as I know, the front calipers were the same through out.

Rich

 

[todd reid]

there has to a slip of the pencil somewhere - there is no way the wheel cylinders are the same diameter as the master!

 

[dtbaker61]

dan,
if you want a .700 master,call doug jennings in dayton ohio. i'm sure he has some in stock.

I may give him a ring, thanks for the number. It looks like there are plenty of .700, .750, .875 masters around.... The single outlet ones are even pretty cheap. The more modern 'tandems' presumably for front/rear would probably still require adding a proportioning valve to balance braking power and are WAY more expensive.

In looking at the original setup, it looks like there is basically NO balancing front/rear, it just splits the single output... is this true? means that any leak anywhere shoots ALL the brakes, right?!

so, I am now wondering what the best balance is for simplicity and cost with a single outlet (boosterless) .700 or .750 master if there is a decent way to split front/back that doesn't get too expensive and might give better performance/safety that the stock method.

 

[65beam]

brakes

the .700 master was original to series 2 alpines. there was no booster and there was no split of front and rear brakes. the line ran from the master to the top of the junction block on the right front inner fender well. one line ran to the right front wheel, one ran across the front crossmember to the left front wheel. another ran to the back and on all the series 2 cars that i have had there was a Y that the line hooked to and a line ran to each wheel. they must not have thought there was a need for a balance valve or proportioning valve. i like the brakes without a booster and i have been driving alpines since 1966 and have never had a total brake failure. you will know if a problem starts to show. my fastbacks have a dual master as a standard factory item. sunbeam went to the dual master in 1968. they had the booster hooked to the front wheels only with no proportioning valves either. the back side of the master feeds the front, the other to the rear. use the .700 master and make sure the brakes are adjusted up and your hand brake cable is adjusted so you can use it to stop if needed.

 

[dtbaker61]

yup, my '62 sII is very stock in this regard, which I am happy with. I LIKE manual brakes, and it will simplify my electric conversion significantly as I will not need a vaccum pump, reservoir and switch.

I was asking in part to verify what i am looking at on my car, and in part to learn more to see if I can reasonably convert a newer car to boosterless.... to avoid the vacuum issues when converting to electric.

the answer at this point appears to be.... either an expensive tandem master, or a non-modern non-failsafe single master with 'simplified' routing for brakelines.

 

[Bill Blue]

You can buy remanufactured F10 master cylinders (tandem dual) for $26 at Rock Auto. Shopping the internet you will find a pair of the small Tilton reservoirs (they fit) and caps will be about $30. Not terribly expensive and most guys are satisfied with the .750" bore.

Bill

 

[dtbaker61]

You can buy remanufactured F10 master cylinders (tandem dual) for $26 at Rock Auto. Shopping the internet you will find a pair of the small Tilton reservoirs (they fit) and caps will be about $30. Not terribly expensive and most guys are satisfied with the .750" bore.

Bill

this gives me great hope! $26 for rebuilt is way better than $250 for the Wilwood! I will go poke around RockAuto.... do you think it will be easier to find the right unit using a make/model/year vehicle, or just sifting through master cyls?

I need to replace/build soon anyway, and this would give me a good way to build in at least separate front/rear with simple Ts, even without 'balancing' would be fine...


I think I need to find out more about check valves and such. I have been reading that the front disc line should have a 2# check valve, and the rear drums should have a 10# check to prevent the knock-back of the pads requiring too much travel when you depress brake pedal.... any thoughts on this? I don't see ANY check on the older system, but maybe it is built into the splitter.

 

[Bill Blue]

There are no check valves and no splitters. No one has ever demonstrated the need for either. The master cylinder that most have used is the 1977 Nissan F10. It will fit with a minimum of aggravation.

Bill

 

[kmathis]

Hi, Dan:

I did the same as Bill on my V6 conversion; bought the F10 dual M/C and the Tilton reservoirs and they work great, I think the pedal force needed is moderate and very comfortable.

 

[dtbaker61]

There are no check valves and no splitters. No one has ever demonstrated the need for either. The master cylinder that most have used is the 1977 Nissan F10. It will fit with a minimum of aggravation.

Bill

fabulous, just the details I needed!

 

[agmason54]

Booster lees brake questions

Why bother swapping masters when the SII master is the perfect application and can be rebuilt for around ten dollars? I run the early masters on all series and toss(now sell)the boosters.
Agm