Dunlop vs. Bonaldi booster/brakes

Leo · Post by **Leo** » Thu Jun 03, 2004 7:53 am

i have always had problems and have been disappointed with my brakes.
i have gone through a few masters and i know that i have the incorrect booster. after driving my car for a while, the brakes start to drag. my
remedy is to pop the hood and loosen the bolts on the master and i am underway again.

i now would like to either get the correct Dunlop C-84 booster for my car, or
find the Bonaldi booster that was found on the later 330's. from serial number 9083 on. did Ferrari
change out the booster for economic reasons, or was the Bonadli a better booster?

can anyone comment on the effectiveness of the brakes in general? is this considered a weak spot for 330's?? and if anyone
has driven both types of booster set ups, can you comment on whether one is better than the other??

i assume that my problem has to do with the adjustment of the rod that
actuates the master; but when i give in a bit more free play the pedal
travel gets excessive. i think that the master and the booster have to
be set up as a unit??

since i am starting at zero, can i simply upgrade to an even newer style
booster from say a 365??

Yale · Post by **Yale** » Thu Jun 03, 2004 9:25 am

I don't know what car you have but I have driven both the early 330's (Series 1) and the later ones (Series 2) and the brakes on the later ones were really good, much better then on the Series 1's I have driven. Can't wait though to try a Series 1 with a rebuilt brake system to see if it is just the state of the brakes in these cars or that they were just ok to begin with. I will say, when I took my Series 1 on the track, the brakes were fine when used under the duress of a 120 mph straight into a hairpin turn. I couldn't believe the brake dust on the wheels. Obviously I was just not tromping on them enough in my normal driving.

Yale

1964 330GT 6097

Leo · Post by **Leo** » Thu Jun 03, 2004 10:28 am

thanks for the reply yale,
do you know which brake system the later series ll car had that you drove? i am not familiar with the early systems, but looking at the parts
book, they seem to have 2 boosters? i guess that when the hanging pedals
came in, they went to the Dunlop C-84 set up and then later with the
Bonaldi.
i guess i am looking for series ll owners to chime in here since the early
cars had a different set up.....and maybe some GTC people to give there
input...

horner · Post by **horner** » Thu Jun 03, 2004 12:00 pm

"Leo", Yale drove mine & kept it on the black stuff between the trees. Dunlop system I believe on 8325.

PS Yale did have a few issues w/ my clutch pedal pressure; some mention of a workout on a Universal gym machine or something!

LJH

Leo · Post by **Leo** » Fri Jun 04, 2004 7:36 am

hey! aren't there a few people out there willing to talk about brakes????

if the standard brakes are set up properly, are they excellent or merely
adequate????

i have seen at least 3 cars, 330GT, 275GTS, and 330GTC that have been
retrofitted with a 70's Bonaldi booster and a longer master that requires
some modifying of the LH inner fender. i was never able to speak with
these owners, but they ALL felt compelled to make this switch for some
reason....and i don't think anyone WANTS to modify original sheet metal
even if its in the engine bay...(one car just had a hole poked out in the
rear portion of the left wheelwell to accommodate it, and another had a
more professional indentation the size of an orange so the master would
fit; the original series ll masters have virtually no forward clearance)

i have read some earlier threads on brakes, but i think its time for more
discussion.....please.....

Art S. · Post by **Art S.** » Fri Jun 04, 2004 8:45 am

According to Francois Sicard, the brakes are Garbage.

Art S.

horner · Post by **horner** » Fri Jun 04, 2004 9:24 am

Is that what that pedal in the middle is!!! My brakes are good, not great. They did well the one time that I tracked the car at Lime Rock, and held up well until I cooked the brake fluid on the second day. Air temp hovering at 100F & Track temp at xxx? didn't help. Having street fluid & not racing fluid didn't help either. Francois gave me a justified earfull for that, as he had flushed and refreshed the system just prior; stupid owner forgot to tell him car was going to LRP. I now run racing fluid (not synthetic) all the time.

330 GTC owners tell me their brakes are worse than ours for at least one reason: same engine & power, lighter car, but smaller diameter wheels (14" v. our 15") & tires, & therefore smaller diameter brakes = faster car w/ smaller brakes. Lots of pucker power for the unwary.

I will try to keep my car as original as possible, so I'll live w/ the brakes. You know what they preach in beginners racing school, BEBO = Brake Early, Brake Often, 'til you know your car & the track/road.

Art S. · Post by **Art S.** » Fri Jun 04, 2004 9:47 am

Jack,

I'm trying to visualize what you mean by "pucker power"!

Art S.

Yale · Post by **Yale** » Fri Jun 04, 2004 10:00 am

I stand by my comment that Jack's Series 2 has very good brakes. As for pucker power Art, I believe Jack is referring to that moment when your brakes aren't doing what you like when you most need them and the part of your anatomy that you're sitting on tightens up in the hope that that will help you stop. Best, Yale

Art S. · Post by **Art S.** » Fri Jun 04, 2004 10:48 am

Yale,

That's exactly what I was visualizing. It also brings back some memories of various driving incidents.

Art S.

Leo · Post by **Leo** » Fri Jun 04, 2004 11:32 am

thanks guys for chiming in!!

an earlier post by fest regarding his 400i booster had some great discussion, but i am not sure i ever read about the conclusion. i think the
cars i mentioned earlier had 400i type boosters fitted. i am also interested in Art's comment regarding Francois "garbage" comment.
maybe Tom can expand on that.

i agree with LJH regarding originality, but i would prefer to replace the
booster/master with something newer if it would signifacantly improve
braking. there must have been a reason, technologically, that Ferrari
kept modifying the booster/master thru production of one model. as
long as i don't have to do any majopr surgery to alter the mounting
points, i'll upgrade.....the trick is finding what to upgrade to??

all the info and discussion is greatly appreciated!!

Art S. · Post by **Art S.** » Fri Jun 04, 2004 2:01 pm

Francois has done some conversions. I think he suggested an M-B setup. If you are serious, you should speak with him.

Art S.

Art S. · Post by **Art S.** » Fri Jun 04, 2004 2:03 pm

I decided to be silly and keep it original. As a result, I've been waiting for parts, without the use of my car, all spring.

Art S.

Chris Coios · Post by **Chris Coios** » Fri Jun 04, 2004 2:21 pm

One of the problems with the Dunlop brake systems, using the Dunlop booster at least, is the capacity of the system under repeated braking. The vacuum is only taken off the last manifold serving 4 cylinders on the 3-carb V-12. As the intake manifolds are not interconnected, the benefit of vacuum from all 12 cylinders is not available. Braking from higher speeds is OK because enough vacuum is generated. The vacuum is not built up very readily, however, during repeated braking from slow speeds. Rolling up to the stop sign at 5 mph can be a source of anxiety when there is no reserve of vacuum. (To some extent, the combination of booster design and master cylinder bore diameter must influence this, but I am not clear on the physics, and I do not fully understand the dynamics of all this.)

Chris

Leo · Post by **Leo** » Fri Jun 04, 2004 3:08 pm

okay! now this is raising a few more questions.....i apologize in advance to those who are devout purists.

1. it seems relatively easy to connect all 3 intake manifolds together.
would this make a big difference in vacuum and would this do anything
to "hurt" idle or performance

2. if the booster does not have the abilty to "store" vacuum well, is it
simply a matter of a larger booster??

i assume that the bonaldi boosters are larger, although i am still concerned
with a 70's or 80's Bonaldi based on the booster thread last year by
Fest. do you have any comments Fest??

from my limited research, it seems like there are only 3 post 1968
Bonaldi boosters, excluding RHD variants. each booster has a compatible
master cylinder of a different diameter. lets say small, medium and large,
with maybe only 1/8" difference between them.

refering to what chris was saying, there must some sort of formula
to explain whether or not a larger diameter master cylinder will exert
more force to the calipers, or is this irrelivent

Art, i will ask Tom to ask Francois about the M-B conversion. i assume
that you are talking about a booster/ master conversion only? it may seem paradoxical to all of you, but i am only interested in doing this if i
can stay with "ferrari" parts. we all have our illnesses.....