Master Cylinder Question

[Senna27]

I've had a very slow brake fluid lead for a little while. After thoroughly checking the brakes, lines and clutch slave, we noticed the bottom of the master cylinder was wet where it attaches to the booster. We suspect the master cylinder is leaking. The OEM master cylinder is not available in Canada but I've found ATE, URO and Centric versions. They range in price from $200 - $267. As far as I know, mine is a stock '75 master cylinder but I do have a tii booster. Thoughts?

 

 

[Mark92131]

11 minutes ago, Senna27 said:

but I do have a tii booster.

 

Yes, swapped to clear your velocity stacks.

 

Mark92131

[halboyles]

Yes that is a ti/tii brake booster.

[Mark92131]

The ATE, URO and Centric Master Cylinders are decent replacements.  You will probably find a pool of brake fluid inside the booster when you pull the master cylinder.  You need to extract that fluid and clean the inside of that Tii/Ti booster before reassembly.

 

Mark92131

 

P.S.  You alternator upgrade is interesting.  I believe the Son of Cobra car has the same one.  Is it a bolt-on upgrade using the stock brackets or custom?

Edited September 5, 2023 by Mark92131
Question

[tech71]

44 minutes ago, Senna27 said:

As far as I know, mine is a stock '75 master cylinder but I do have a tii booster. Thoughts?

Need to confirm your master cylinder is in fact, a non tii unit.

I am unsure if they are interchangeable 

Tii units are going to be a problem, recent traffic on the forum and associated search indicates they are close to unobtanium status.

Edited September 5, 2023 by tech71

[Mark92131]

1 hour ago, tech71 said:

I am unsure if they are interchangeable 

 

They do interchange.  The difference is the internal  bore (23.81mm on the Tii and 20.61mm on the standard 2002).

 

Mark92131

[halboyles]

1 hour ago, tech71 said:

Tii units are going to be a problem, recent traffic on the forum and associated search indicates they are close to unobtanium status.

You are correct, sir!

 

That is except at 2002s Only we have completely rebuilt ti/tii brake boosters in stock and no core is required.

 

M10 tii/ti Brake Booster | 2002s Only

WWW.2002SONLY.COM

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That’s right! We have the ATE T51 brake booster used on the 2002ti, 2002tii and 2002 Turbo in stock. This is the 7” diameter, dual-diaphragm boosters used to accommodate the side draft carburetor and fuel injection intakes on these higher horsepower 2002’s. We’ve taken ATE T51...

 

Problem solved!

[Senna27]

5 hours ago, Mark92131 said:

The ATE, URO and Centric Master Cylinders are decent replacements.  You will probably find a pool of brake fluid inside the booster when you pull the master cylinder.  You need to extract that fluid and clean the inside of that Tii/Ti booster before reassembly.

 

Mark92131

 

P.S.  You alternator upgrade is interesting.  I believe the Son of Cobra car has the same one.  Is it a bolt-on upgrade using the stock brackets or custom?

 

Okay, good to know about those replacements. I figure the brake fluid is leaking into the booster. 

 

My mechanic installed that alternator. I'm not 100% sure, but I believe it uses the stock brackets with little to no modification. 

[Senna27]

3 hours ago, Mark92131 said:

 

They do interchange.  The difference is the internal  bore (23.81mm on the Tii and 20.61mm on the standard 2002).

 

Mark92131

 

Is that so? If it's virtually identical, dimensionally, and I don't have to make any modifications, it would make sense to get the tii version. As it is, I have tii front struts and brakes. Finding a new one may prove to be a little more difficult. 

[tech71]

4 hours ago, halboyles said:

That is except at 2002s Only we have completely rebuilt ti/tii brake boosters in stock and no core is required

I was referring to the Tii master cylinder  becoming unobtainium  not the servo but ok..

Free plug 

I installed a URO master cylinder 2 years ago to replace blown out original, so far so good.

Edited September 5, 2023 by tech71

[TobyB]

Quote

The ATE, URO and Centric Master Cylinders are decent replacements. 

 

Messed that up for ya. 

ATE is, at last unboxing, still a high quality German manufacturer.

The other 2 are not.

 

That's a NipponDenso (ND) alternator. 

Popular on about a bazillion cars in the junkyard.

The 50 amp version's a bit hard to find- Subaru Justy for the tii.

I used Chevy Sprint ones for the non- tii, but ya have to make a bracket.

You can get them from race shops, too, now.

 

t

 

[Senna27]

What about this replacement from IE. How is it quality wise? Has anybody installed one of these? Is it a direct swap or would I have to modify brake/supply lines?

 

 

Brake Master Cylinder – Tii/2800CS – Ireland Engineering | Racing & Performance Parts for BMW & MINI

WWW.IEMOTORSPORT.COM

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Each

 

[Mark92131]

1 hour ago, Senna27 said:

Is it a direct swap or would I have to modify brake/supply lines?

 

It will be a direct swap for your 75.  

 

Mark92131

[Senna27]

2 minutes ago, Mark92131 said:

 

It will be a direct swap for your 75.  

 

Mark92131

Perfect, thanks. I just put my car on the hoist and I’m standing underneath it. As you said, the master cylinder appears to be the identical size and shape. 

[Mike Self]

Before you go swapping out master cylinders...look very carefully at the two hoses that link the reservoir to the M/C (they should be blue cloth, not black) then examine the plastic nipples and their rubber grommets for moisture (i.e. brake fluid).  The hoses can ooze when old, and the nipples can crack, as well as the rubber grommets,  Be a shame to replace the M/C only to find leaking hoses...

 

mike