my (recently purchased) 1980 400i
requres a downright herculean effort
on the brakes to stop the vehicle
upon first application and start of driving
once the car is fully warmed up
(and after a few vigorous applications)
the braking effort required to stop
improves to merely excessive
- 'locking up' the brakes is out of the question
(at least at velocities > 40 mph)
this normally would indicate (to me) a problem
however, when I test drove a 1979 400A
I noted the same 'heavy' pedal
and excessive effort to stop the vehicle
especially in a rapid fashion
(that did improve somewhat with use)
the fact that 2 different cars with different mileage and condition
having the same braking characteristics
would lead one to believe that:
1) These cars are 'like that' (I find it hard to believe that such poor brakes would be the norm)
2) This problem is endemic to these vehicles
3) This is the result of car sitting for several months unused
input (especially from you 400 owners) vastly appreciated
400i: Braking Effort
Brakes
The typical old Ferrari brake problem is internally-collapsed flexible brakes lines at the wheels. If you try to bleed the brakes and can't get much fluid out, this is a likely cause.
Deane
'67 330GTS (gone but not forgotten)
'67 330GTS (gone but not forgotten)
I am not a 400 owner I have a 330GT. An earlier car which leads me to believe that your brakes would be better and more developed. That said when I bought the car I was quite happy with the braking of the two booster system which over the two years I have owned it (and driven it quite often) has degraded to a degree that makes me think it may be time for a booster rebuild. I would conjecture that you have now driven two 400's that need a rebuild instead of one.
I couldn't figure out why my brakes were intermittently off until I went to the track, that 180 degree turn at the end of the long straight at Lime Rock really had me standing on the brakes as such the front wheels were black with brake dust. I realized I hadn't really been using the brakes up till then as I have never driven car that you needed to stand on the brakes and didn't realize that WILL stop the car. As a postscript I drove Jack Horner's Series 2 330GT (I have a Four Headlight), and his brakes were fantastic. His clutch on the other hand need you to have the thighs of Jack Armstrong.
Best Yale
I couldn't figure out why my brakes were intermittently off until I went to the track, that 180 degree turn at the end of the long straight at Lime Rock really had me standing on the brakes as such the front wheels were black with brake dust. I realized I hadn't really been using the brakes up till then as I have never driven car that you needed to stand on the brakes and didn't realize that WILL stop the car. As a postscript I drove Jack Horner's Series 2 330GT (I have a Four Headlight), and his brakes were fantastic. His clutch on the other hand need you to have the thighs of Jack Armstrong.
Best Yale
booster / master cylinder assembly
The brake service is up to date on the car
and has been bled regularly
(at least for the past 5 years or so)
I plan to do a thourough visual inspection of the system
and bleed / flush
(that should tell me if I have collapsed hoses)
but I am not hopeful about the results
i.e. I do not think merely bleeding the brakes
will solve all my braking issues
I tend to think it is the booster myself
I plan to disconnect the vac line
to the booster and see if that makes any difference
I am also planning to do the 'thumb' test
i.e. see if there is sufficient vacuum
by placing my thumb over the vac hose
the vac pump seems to be working ok
i.e. it is not noisy
and the vacuum modulator on the tranny
seems to be working ok
so I do not think the vac pump is the problem
the workshop manual does not devote much space
to the brake booster... merely says to replace it
some specs on how much vacuum the pump is suposed to pull at idle
or how much vacuum should be expected
in the vacuum supply line at the booster, etc
would be a big help...
how can i tell if my booster is shot?
test w/mityvac?
suggestions?
the brake light also flashes when brakes are applied
and then goes out as the brakes start to work
pedal seems to sink a little when stopped
(when waiting at a light, etc)
and will not 'pump up'
(like when there is merely air in the system)
and I have not found any leaks
this to me would seem to indicate that the master cyllinder is worn
and the fluid is leaking past the 'cup'
this may explain the flash of the brake light
if one circuit does not build pressure
as rapidly as the other due to wear
in this case, it wold seem prudent to replace
the booster / master cylinder assembly
but I want to confirm this is the solution
before I make the investment
and has been bled regularly
(at least for the past 5 years or so)
I plan to do a thourough visual inspection of the system
and bleed / flush
(that should tell me if I have collapsed hoses)
but I am not hopeful about the results
i.e. I do not think merely bleeding the brakes
will solve all my braking issues
I tend to think it is the booster myself
I plan to disconnect the vac line
to the booster and see if that makes any difference
I am also planning to do the 'thumb' test
i.e. see if there is sufficient vacuum
by placing my thumb over the vac hose
the vac pump seems to be working ok
i.e. it is not noisy
and the vacuum modulator on the tranny
seems to be working ok
so I do not think the vac pump is the problem
the workshop manual does not devote much space
to the brake booster... merely says to replace it
some specs on how much vacuum the pump is suposed to pull at idle
or how much vacuum should be expected
in the vacuum supply line at the booster, etc
would be a big help...
how can i tell if my booster is shot?
test w/mityvac?
suggestions?
the brake light also flashes when brakes are applied
and then goes out as the brakes start to work
pedal seems to sink a little when stopped
(when waiting at a light, etc)
and will not 'pump up'
(like when there is merely air in the system)
and I have not found any leaks
this to me would seem to indicate that the master cyllinder is worn
and the fluid is leaking past the 'cup'
this may explain the flash of the brake light
if one circuit does not build pressure
as rapidly as the other due to wear
in this case, it wold seem prudent to replace
the booster / master cylinder assembly
but I want to confirm this is the solution
before I make the investment
As the owner of a 400i for the past 4+ years, I can tell you that the normal brake operation is excellent with no extreme effort needed on the pedal. The brakes haul you down very quickly with no more effort than on my Mercedes.
Sounds like the booster would be a good place to check.
Good luck,
John Ashburne
1983 400i 5 speed, silver/black
Sounds like the booster would be a good place to check.
Good luck,
John Ashburne
1983 400i 5 speed, silver/black
booster
thanks john
all signs are pointing to the booster
I had the front wheels off this weekend
and all was in order
(not even a drop of fluid any where)
I plan to inspect the rears next week
I plan to then bleed the entire system
and check for vacuum leaks
if everything is in order
I will then proceed with booster replacement
all signs are pointing to the booster
I had the front wheels off this weekend
and all was in order
(not even a drop of fluid any where)
I plan to inspect the rears next week
I plan to then bleed the entire system
and check for vacuum leaks
if everything is in order
I will then proceed with booster replacement
How are you getting on with your brakes? I ask because your symptoms are almost identical to my 400 Auto - my brakes get better as they get hot but they are not what I would call good brakes. I have changesd the front discs, all the pads, the booster and rebuilt all the calipers. My brake light also comes on as you describe. This light is activated by the vacuum switch on the booster (if I disconnect the vacuum switch wire the light stops flashing). I am wondering if it could be the one of the two one-way valves in the vacuum lines.
BTW if you want a booster I have an almost new one you can have at a sensible price. I changed mine when I first bought my car because the brakes felt poor, I drove on the new one for four years and eventually convinced myself that my mechanic had fitted the wrong booster. I bought another new one and the brakes were the same, used if for a couple of hundered miles and swopped it back out with the first 'new' one. Ferrari refused to take it back as it had been 'used'. Fair enough I suppose, as it's a safety item. Costs new around £270 (about $400) here in London. You can have it for half price plus shipping. I can post a picture if you want.
Simon
BTW if you want a booster I have an almost new one you can have at a sensible price. I changed mine when I first bought my car because the brakes felt poor, I drove on the new one for four years and eventually convinced myself that my mechanic had fitted the wrong booster. I bought another new one and the brakes were the same, used if for a couple of hundered miles and swopped it back out with the first 'new' one. Ferrari refused to take it back as it had been 'used'. Fair enough I suppose, as it's a safety item. Costs new around £270 (about $400) here in London. You can have it for half price plus shipping. I can post a picture if you want.
Simon
booser
Dear Simon
no work on brakes lately as I was working on the hood strut thing
(no progress to report there either, I am afraid, as my truck needed it's 100K service)
as stated, I was hesitant to shell out the $ or (£) for a new booster
until I had a solid diagnosis to go on
(these parts are just too damn expensive to play swap out)
I also agree that the vacuum supply
bears some invesitgation
I had noticed the vacuum switch on the booster
(which is not mentioned in the service manual btw)
and had planned to experiment with that
and see if that was the source of the brake light...
seems like you have confirmed that therory
checking the one way valve is a good idea
maybe it is just plain old leaky hoses
(I am going to check all the hose clamps to start with)
I still as yet have to inspect the rear brakes
and I plan to bleed the system as well
but am not expecting any miracles
as for the brake booster, I am interested
but will it fit?
I show P/N 124518
LHD and RHD
(or GS and GD)
are NOT interchangeable
(as far as I know)
no work on brakes lately as I was working on the hood strut thing
(no progress to report there either, I am afraid, as my truck needed it's 100K service)
as stated, I was hesitant to shell out the $ or (£) for a new booster
until I had a solid diagnosis to go on
(these parts are just too damn expensive to play swap out)
I also agree that the vacuum supply
bears some invesitgation
I had noticed the vacuum switch on the booster
(which is not mentioned in the service manual btw)
and had planned to experiment with that
and see if that was the source of the brake light...
seems like you have confirmed that therory
checking the one way valve is a good idea
maybe it is just plain old leaky hoses
(I am going to check all the hose clamps to start with)
I still as yet have to inspect the rear brakes
and I plan to bleed the system as well
but am not expecting any miracles
as for the brake booster, I am interested
but will it fit?
I show P/N 124518
LHD and RHD
(or GS and GD)
are NOT interchangeable
(as far as I know)
My booster is PN 124519. The RHD and LHD are almost the same the difference is minimal. When you stand in front of a RHD car and look at the servo, and imagine you are looking at a clock face, the vacuum connection is where the 8 would be. On a LHD (US) car it is where the 4 is. This is the only difference that I can see. You could either fit hoses which are about 6 inches longer or you can unbolt teh booster section from teh master cylinder, turn it 90 degrees and bolt it back together again - this is easy to do as far as I can see because they are joined by four bolts.
may work
Simon-
I have looked into it as well
the only difference
does appear to be
in the location of the Vacuum outlet
I am definately interested...
can you send pics to thefest@msn.com?
thanks
also
have you tried disconnecting the vaccum lines
(and plugging them off)
and seeing if that affeects the braking at all
i.e. gets worse or no effect
that's how my brakes feel
like there is no vacuum boost
(like when the engine is off)
AKB
I have looked into it as well
the only difference
does appear to be
in the location of the Vacuum outlet
I am definately interested...
can you send pics to thefest@msn.com?
thanks
also
have you tried disconnecting the vaccum lines
(and plugging them off)
and seeing if that affeects the braking at all
i.e. gets worse or no effect
that's how my brakes feel
like there is no vacuum boost
(like when the engine is off)
AKB
OK, I have sent the pics to you.
Actually I have not tried driving the car with the vacuum hoses disconnected. I removed the hoses from their connection at the booster and there is vacuum in both (one from the inlet manifold and one from the vacuum pump). As the booster is new I didn't drive it like that to see how the brakes feel. To be honest it never occured to me. I will give this a try but I am sure there is some assistance being given. I have been 'driving' the car when it was being pushed around a workshop and the brakes are almost non-existant.
I must say that mine feel like they are working OK but that they are only getting about 75% of the assistance they need.
Actually I have not tried driving the car with the vacuum hoses disconnected. I removed the hoses from their connection at the booster and there is vacuum in both (one from the inlet manifold and one from the vacuum pump). As the booster is new I didn't drive it like that to see how the brakes feel. To be honest it never occured to me. I will give this a try but I am sure there is some assistance being given. I have been 'driving' the car when it was being pushed around a workshop and the brakes are almost non-existant.
I must say that mine feel like they are working OK but that they are only getting about 75% of the assistance they need.
Here is an interesting article about brakes from FCA South West region:
http://www.fca-sw.org/sw/article.asp?id=422&feature=2
http://www.fca-sw.org/sw/article.asp?id=422&feature=2
I had a similar problem with my 330-culminating in no stopping power eventually (no fluid leak but softer pedal until it eventually went to the floor).
Fixed by getting the master cylinder re-sleeved as well as the two boosters by white post in VA. The mechanic actually rec. the re-sleeve vs finding some NOS parts as those might be just as old as the original parts.
With it fixed the car stops well, but effort is variable, especially in stop and go driving-I guess in some cases there isn't enough vacuum built up in between brake applications.
White post returned the parts looking good on the outside as well.
Fixed by getting the master cylinder re-sleeved as well as the two boosters by white post in VA. The mechanic actually rec. the re-sleeve vs finding some NOS parts as those might be just as old as the original parts.
With it fixed the car stops well, but effort is variable, especially in stop and go driving-I guess in some cases there isn't enough vacuum built up in between brake applications.
White post returned the parts looking good on the outside as well.
booster GD
thanks for the advice guys
I hait the shop tomorrow!
(hood struts first, tho)
simon
got the pics
Booster looks like it will fit
BUT
the Master Cylinder
has the outlets on on the wrong side
(the casting looks interchangeable)
I will check it out tomorrow
AKB
I hait the shop tomorrow!
(hood struts first, tho)
simon
got the pics
Booster looks like it will fit
BUT
the Master Cylinder
has the outlets on on the wrong side
(the casting looks interchangeable)
I will check it out tomorrow
AKB