Removing BBi Brake Master Cylinder

Has anyone experience or tricks to help remove the brake master cylinder in the BBi? I have had a "dead" spot in my brake pedal that leads to occasional palpitations. Initial pedal resistance, then free pedal until halfway down, then firm pedal and braking. Decided to drain and refresh brake fluid, and to clean reservoir off the car. In discussing with a few Ferrari experts, they suggested master cylinder may be culprit. Hence, since the lines are drained I decided to rebuild the master at the same time.

Problem is: The 4 nuts (13mm) that hold the master to the booster are in such proximity to the master that a socket cannot fit - even a thin-walled socket. The two forward nuts are easy to remove with a spanner. However, the two rear nuts do not lend themselves to a wrench - too tight a space under the dash to swing the spanner. I hope that I do not have to remove the booster and master as a unit.

Any help is appreciated.

Jim S.

 

Jim,

You must have been reading my mind, as I'm about to pull the MC on my 365bb due to a "bypassing" problem. I pulled the MC about 20 years ago and do recall that it can be removed separately without too much ado. Let me take a look in the morning and hopefully, I'll have some suggestions.

Regards,
David

 

Successfully removed master cylinder...needed the correct thin-walled, short, swivel socket.

Has anyone an assembly diagram or photograph of the springs, seals, and washers from the Benditalia master cylinder?

Jim S.

 

From my 308, same brand. Dont forget to undo the little hidden screw down inside one of the supply ports. It fits in the slot in the piston and limits its travel. Cost me 25GBP for the kit to rebuild mine.
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Paul - thanks for posting the photos. The 308 appears to be a little different from the Boxer, but I can see what I need to. The seals are a bit different as well.

Has anyone a picture of the Boxer master cylinder? The kit I received from GT Car Parts has only 4 of the "donut" rubber seals. I believe that I need three. The larger seal with the goove sits behind the large washer and snap ring. This was not included in the kit. Any ideas where I might find one.

Thanks for the info on the removing the threaded "stop" in one of the ports. I have come across this same situation in my Dino and my Alpine, so it appears to be a common practice.

Jim S.

 

Dear Ferraristi,

Wow....if only the TR portion of the forum had stuff like this !


Just wondering, I have a couple of drips from my clutch master cylinder. (91 Testarossa US ) Is there a rebuild kit for that?

Thanks,

Shamile

Freeze....Miami Vice !

 

Not what you need, but here's the TR MC drawing from the TR WSM for reference. Is the BBi MC significantly different internally?
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Steve - your MC from the TR appears identical to the BBi. Thank you very much. More to come.

Jim S.

 

Jim,

I appologize. I haven't had a chance to get mine pulled...
Hopefully today and I'll post some pictures of the internals.

Regards,
David

 

Thanks David - I have mine back together and mounted in the car. I won't know until the first test drive whether I assembled it correctly. Now to bleed the system. I may take a run to Sears today looking for some form of pressure or vacuum bleeder.

Jim S.

 

Jim,

Glad to hear that yours is back together. I got mine out this morning, with the help of a thin-wall 13mm socket, on a 1/4" drive wobbly drive. Not too bad, after all...

My master cyclinder is a 25.4mm Bonaldi unit that doesn't have a "lock bolt" limiting travel...(Then, again, I didn't look in the secret spot yet, as Paul outlined above). The bore was stamped on the "cap end" and agreed with the WSM. Do you recall what the diameter of yours was?

Too bad your not on the other Coast, as you'd be welcome to use my pressure bleeder. The cap size is a standard "ATE" thread, which is even used on modern day BMW's and Audi's...as well as most all Ferrari's.

David

 

David - thanks for the offer. I spent most of the morning looking for a pressure bleeder, and settled on a vacuum hand pump bleeder from Harbor Freight. Once I put teflon tape on all of the bleed screws it went like a breeze. The $30 plastic pump actually worked well.

I got all of the bad old stuff out along with air. I have yet to drive the car, but I do notice a fair amount of free play travel in the pedal. Is there an adjustment at the pedal to remove an inch of free pedal travel?

While the car was up I took out both alternators and removed the valve train oil return hoses on both sides. This entailed removing the flange at the bottom of the valve covers (forward aspect), cleaning oil from everywhere, and reinstalling with new flange gaskets and silicone hoses. I hope this was the source of the dripping. Changed oil and filters (Fram PH2804-1).

Hope to have it all bottoned up tomorrow for a drive.

Any help on the free pedal travel is greatly appreciated.

Jim S.

 

Jim,

Those bleed screws leak pretty badly, as you found out. The 365 has threee bleeders per caliper, so I gave up on the vacuum bleeding a long time ago and reverted to the "helper" method as I can't use a pressure bleeder on my car due to the unique dual reservoirs. There is a "free play" adjustment, though it is highly unlikely you need to adjust it, as the adjustment is set at the factory and usualy only needs to be changed if a new master is installed, which has a different push-rod lenght. You can access the adjuster by removing the cover from the pedal box (from under the front bonnet). I believe that the spec is .003", but I'd verify that info in the WSM as I'm doing this from memory. If you need a picture of the process, let me know and I'll scan the page. Personally, I'd drive the car first...and verify the feel, as the brake pedal has an odd feel without the car running. If play, or softness still exists, I'd, with the help of an assistant, bleed the lines at the master.

I too have had in the past oil seepage problems at the valve cover return hoses. I finally gave up on the expensive, short lived, over priced Ferrari hoses and went with a "special purpose" multi-layer silcone hose from Federal. I buy it in 3 foot lengths...and the stuff works great.

With all the (old?) bad press on the Fram PH-2804-1, I switch over to Baldwin many years ago. For the Boxer application, the filter is B-252, although you can (and I do) use the B-253, which has a built-in check valve for inverted applications. As I have owned and now service other V-8 and V-6 Ferrari's, I can use the B-253's on everything.

David

 

David - the teflon is necessary only when using a vacuum method on the bleed screw. Air can leak past the bleeder valve threads and lead you to falsely believe there is air in the system. The teflon allows you to loosen the bleed screw while still maintaining a seal to the thread.

The 512 also has three bleed nipples per caliper. A bit more time required, but no challenge here.

The dual reservoirs are really just one chamber. There is internal communication over the center baffle. I examined the dual fill and dual feed reservoir of my 512i and learned that I could fill both sides from one cap. Hence, a pressure system will work.

Yes, I will drive the car first before attempting any pedal adjustment. It may be that the pads have to settle again. Or something.

Thanks for all the comments and help.

Jim S.

 

David - in response to your private e-mail - the "rebuild" kit supplied by GT Car Parts is simply 4 "donuts", the rubber seals that sit inside the master cylinder. I only needed three of them (one of us is confused). The kit did not include the flat-profile large rubber seal that sits behind the washer and circlip at the booster end. Nor did it include the rubber plugs that receive the plastic fittings feeding reservoir fluid to the master cylinder.

The master cylinder in my Boxer (injected) is Benditalia. By the way, I believe that many of the Italian cars of the era used either the Benditalia or another Bend...., both representing subsidiaries of Bendix of North America. Hence, the fittings of the Dino MC are SAE thread, not metric. As I did not change the hard lines or fittings during this service, I cannot comment on whether the Benditalia has SAE threads, but the Dino MCs have SAE threads for the brake line fittings. This is important to know because many of us do total restorations, including hard brake lines. All fittings on the Dino are metric, with the sole exception of the MC. Hence, if you purchase a bunch of metric fittings and hard line, you will either be unable to get the fitting to connect to the MC or you will strip the MC while trying.

I experienced similar difficulty with my Dinos when purchasing MC rebuild kits...there are none. GT Car Parts is good enough to stock the necessary items that require refreshing, but not all items.

Jim S.

 

Jim,

The 365 has dual separate, remote mounted, fluid reservoirs, one for one section of the master, and the other for the other section. Other than a interconnecting hose on the top of these reservoirs to equalize fluid levels, if one were to overfill an individual reservoir, there is no interaction. My reservoir caps have an integral rubber bellows which expands as the fluid level drop due wear. When I attempted to pressure bleed one of these reservoirs, with a "universal clamp-on adapter", it just pushed fluid out the other reservoir seal...

I believe that the 365bb is the only Boxer that uses this set-up, hence the manual, or vacuum-type bleeding procedure.

Appreciate the info on the MC kits. It seems that most Boxers use the Benditalia masters, whereas the 365 uses the Bonaldi unit...

David

 

David - sorry for my inaccurate report on the dual reservoir. I assumed (bad assumption) that the reservoir in the BBi was similar to the 365.

I did have to shorten the adjustment rod above the foot pedals to remove free play. The effect is opposite what you might first think (lengthen rod to remove free play). In fact, owing to the linkage pivot, one must shorten the rod to move the actuating rod closer to the booster.

Jim S.