Alfa Romeo Forums banner

1 - 20 of 33 Posts

·
Registered
Joined
·
429 Posts
Discussion Starter #1
Hi Everyone,
I have seen several GTVs with hanging pedals that have deleted brake boosters.
Does anyone know what type/size and where I can possibly purchase a brake master cylinder that would bolt directly to the pedal box assembly? Or is there an "adapter" that is available?
For clearance purposes, I'm planning on removing the brake booster on my '74GTV.
Any assistance will be greatly appreciated.
Thank you!
 

·
Registered
Joined
·
228 Posts
well, very early giulias didnt have a booster...In my opinion, except the extra force needed for braking (needs really heavy foot here), system will be still working fine. I have a Giulia which had originally 2 boosters and floor pedals and deleted both since they were leaked and were not decent, braking now is more rapid but as mentioned need a very heavy foot. But this is only and nothing else. However, if money isnt an issue and you must be completely original, the best will be to repair the booster or the boosters or buy new ($$$both...)
 

·
Registered
Joined
·
173 Posts
Alternate master cylinder

new2alfas-

I read here on the board that a BMW 2002 mc (Ate, IIRC) is a direct replacement. It has a 20 mm bore (down from the GTV's 22mm) to increase the leverage. All the brake lines attach in the same places and the bolt pattern is the same, but you will need a spacer the same thickness as the booster.

I haven't done this, so I have no direct experience. I only remembered it because it sounds like a great solution. The poster said the brakes felt great and were not too heavy.

Let us know how it works out!

~Chris
 

·
Registered
Joined
·
429 Posts
Discussion Starter #4
Brake booster delete

Thanks for you input alfaroad. As i mentioned, i'm doing it for space issues.
Chris, I will go ahead and check out the BMW 2002 MC. I hope it works!
Thank you!
 

·
Super Moderator
Joined
·
11,775 Posts
I read here on the board that a BMW 2002 mc (Ate, IIRC) is a direct replacement. It has a 20 mm bore (down from the GTV's 22mm) to increase the leverage. All the brake lines attach in the same places and the bolt pattern is the same, but you will need a spacer the same thickness as the booster.
Substituting a 20mm dia MC for a 22 would result in more line pressure for the same force applied to the pedal. There would be more pedal travel, but it would all probably work.

desmo veloce points out that you'd need a "spacer" to adapt the MC to the casting that holds the pedals and booster. I'd call it an adapter - it would need four studs at the back positioned to fit into the holes where the booster had bolted, and two studs at the front to accept the MC. You would also need to make some modification to the push rod between the pedal and MC.

Keep in mind that the booster includes the bracket for the clutch MC. You would need to somehow replace that bracket if you deleted the booster.

In summary, that "spacer" will be a fairly complicated part.

new2alfas: Tell us more about those "space issues" you are trying to solve. Installing a big block Chevy, are we?
 

·
Registered
Joined
·
5,303 Posts
In the early 105's, that's the exact choice Alfa made: 22 mm MC for single booster, 20 mm for no booster. You get 10% more pedal travel for the same braking effete, hence 10% less force over the larger MC with no booster. I agree that the no-booster system feels "crisper". On a track car it works very well with an adjustable Tilton rear brake valve.

Robert
 

·
Registered
Joined
·
429 Posts
Discussion Starter #7
brake booster delete

Alfajay, I plan on installing a race header and because of the header design, it would be best if the booster was not in the way.
A Chevy motor in an Alfa? That would be sacrilege!
 

·
Super Moderator
Joined
·
11,775 Posts
22 mm MC for single booster, 20 mm for no booster. You get 10% more pedal travel for the same braking effete, hence 10% less force over the larger MC with no booster.
Not to pick nits, but you'd get 21% more pedal travel to displace the same amount of fluid. That's because the ratio is a function of the pistons' areas, and those areas are proprotional to the square of the diameter. So (22/20) ^ 2 = 1.21

new2alfas said:
A Chevy motor in an Alfa? That would be sacrilege!
Yes, it would.
 

·
Registered
what part?
Joined
·
10,926 Posts
andrew make a mount for a brake master cly, with out the booster.. and i am running 4 pot calipers( alumiumn ) with vented disk, on my spider with out the booster.. easy to stop the car.. no need for a heavy foot.
 

·
Trained (ex)Professional, , 1953-2018 RIP
Joined
·
16,232 Posts
I will go ahead and check out the BMW 2002 MC.
No need to go with a BMW unit. 115 cars from, I think, 1975 on were fitted with 20mm masters from the factory. All the usual Alfa suppliers should have them.

davbert,
The Alfa underfloor tandem masters came in 22mm only. Can't say if other car makers used a different size though. If they did, adaptability may be an issue.
I see 4 options;
1) delete the boosters and be done with it.
2) have your master sleeved to 20mm. But then there's the issue of procuring, or having made, 20mm pistons. Then determine what seals to use.
3) install calipers with slightly larger piston diameters.
4) change the brake pedal ratio by moving the master clevis higher up on the pedal pivot arm.
 

·
Registered
Joined
·
429 Posts
Discussion Starter #13
Brake Booster delete

Thanks for your input Papajam!
Since it looks complicated and could be costly, I think it's best if I would just have the header I intend to install re-designed.
I wish someone would come up with a "bolt-on kit" and market it...? Papajam?
 

·
Registered
Joined
·
410 Posts
Kpc655 used a booster replacement adapter made by Anthony Rimicci in his race car buildup. Perhaps you could contact either of them for help.
 

·
Super Moderator
Joined
·
11,775 Posts
any smaller 20mm mc available for the floor pedal twin circuit 69 master cylinders?
If your objective is to delete the two boosters, another alternative would be to install a 20mm single circuit MC. While the '69 dual circuit MC isn't available in a 20mm version, the earlier, single circuit MC is.

This would take quite a bit of re-piping, but if you intend to do a neat job of eliminating the boosters (e.g., not just using two unions to connect the boosters' inlet and outlet lines), then you have some tubing cutting & bending ahead of you anyhow.

There was a long thread on the topic of deleting boosters on standing pedal cars last week. See http://www.alfabb.com/bb/forums/gt-1965-1974/183675-2-servos-not-2-servos.html
 

·
Trained (ex)Professional, , 1953-2018 RIP
Joined
·
16,232 Posts
I did not list downgrading to a single circuit as an option because, quite frankly, it is NOT an option (IMHO, of course). If fact, those who are charged with an at fault crash because of this modification should be sued into poverty and banned from driving for life. It is, IMO, one of most irresponsible modifications one can do.
 

·
Registered
Joined
·
5,303 Posts
Jim, That's WAY to extreme. While dual ccts can have a small safety benefit, almost any accident that a single cct failure contributes to would still occur with a dual cct failure, or a booster failure, or a number of other problems of driving a 40 year old car.

Many BB members have had trouble bleeding dual cct brakes; that could contribute to more accidents than single cct issues because it is a common problem; whereas a cct failure, single or dual, is still very uncommon. I suppose you'd sue the pants off them too? And what about the failures or mis-operation of the brake limiter, or failures of the booster(s) that collects brake fluid in the booster itself?

A dual cct system is NOT automatically more reliable than a single cct system. It has ONE slightly better failure mode (rear brake cct fails), but because of the added complexity (especially with a 40 year age), the total system reliability is lower than a single cct system.

Redundancy is a nice concept for safety, but it must be well engineered and well maintained. The early Alfa system of dual boosters and dual asymmetric ccts is neither. It was implemented to meet a regulatory requirement, not as a significant engineering change, as demonstrated by Alfa dropping it for the hanging pedal approach barely a year later. Even that design fails to implement the requirement of dual INDEPENDENT systems; all Alfa dual cct systems have several common single-point failure modes.

Robert
 

·
Trained (ex)Professional, , 1953-2018 RIP
Joined
·
16,232 Posts
You are confusing a brake component failure, which can happen on any vehicle, with willingly and knowingly modifying a major safety system.

There's a BIG difference.

And yes, I think vehicular homicide is WAY too extreme.
 

·
Registered
Joined
·
5,303 Posts
So you consider this whole thread to be illegal and immoral. Deleting one booster is also modifying that system. Changing the brake calipers is too. Is using different (non OEM) pads too?

If modifying an unreliable dual cct system is immoral, isn't driving an older single cct system also? After all you should "know" it's not as safe as a "better" one. How far do you want to carry this? Perhaps we should scrap all these "old, unsafe" cars. That's certainly the position Ralph Nader took on the Corvair. Your position has no legal basis (several modified hot rods have been in crashes without exceptional consequences), certainly no engineering basis, no liability basis (as reflected in the available insurance rates). It's very emotional, and smacks of irrational thinking. Did something happen to lead you to this?

I take the exact opposite view. I know old cars are not as good as new ones, so I drive a recent BMW, Toyota Camry, or GMC truck for all my significant driving needs. I drive my Alfas as a reprieve, to experience a bit of the simpler times I grew up in. I do not drive them aggressively except on the tracks, and even there I don't drive 11/10ths like I did as a young racer. A thousand miles a year is more than I get.

As as career systems engineer, I approached this thread analytically. The simpler system is easier to maintain at full capability. They are still 40 years old, and use 40 year old parts! I've had later Alfas with dual cct systems, and have experienced all the troubles in bleeding and maintaining them that others on the BB have from the day they were new! I've NEVER had any trouble with single cct brakes (I didn't even have a single booster in my racers 'tho the CAS recommended it).

Jim, I deeply respect the engineering expertise you offer to the BB. It's always well reasoned and deep in real world experience, way beyond my own. But You seem to be very emotional about Alfa brakes in several threads. I hope you didn't have a loved one injured over something.

Whatever the reasons, I apologize for rubbing on a sore spot; please forgive me. I just have this (bad) habit of challenging unsupported or unexpected notions. It's something my dad taught me as a tool to better understand technical issues as well as the personal positions of others around me. I'll sometimes take a position I don't even agree with for these reasons. It's helped me to some soaring accomplishments, but has left a few angry people who I would prefer to call friends; you are certainly one of those (people I'd prefer to call friends)!

Robert
 

·
Super Moderator
Joined
·
11,775 Posts
I did not list downgrading to a single circuit as an option because, quite frankly, it is NOT an option (IMHO, of course). If fact, those who are charged with an at fault crash because of this modification should be sued into poverty and banned from driving for life. It is, IMO, one of most irresponsible modifications one can do.
Well, Jim does raise a valid point. I was speaking from a technical perspective - want a 20mm MC, and a dual circuit isn't available? Well, you could substitute a single circuit. It works on '65 - '67 Alfas, so it should work in a '69.

But from a legal perspective, this may well be a bad idea: If you converted your Alfa from dual to single circuit brakes (or if you deleted one or both boosters), and if you were involved in a serious accident, the opposing attorney could have a field day. Imagine sitting at the defendents table, while some prosecuting attorney railed on:

- Not only was the defendent driving a 45 year old car!
- Not only was this car not maintained by a professional mechanic!!
- But he intentionally removed one of the car's braking systems!!!

Admittedly most jurors won't have a clue what this is all about, but it does sound pretty negligent. And, although accident might have had nothing to do with brake failure, you probably would be hosed.

So if this happens to you, don't tell the judge it was alfajay's idea.
 
1 - 20 of 33 Posts
Top