OEM, OEM quality or value engineered?

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miker
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OEM, OEM quality or value engineered?

Post by miker » Sun Jun 16, 2019 8:16 pm

I almost put this in the B.S. section.

I've attached photos of three different master cylinders. The first one is OEM Fiat, the second is from a branded manufacturer, and the third is of unknown origin. The configuration of this MC is unusual in that two of the rear outlet comes out of the side and goes to the rear brakes, the front outlet you can see goes to one front disk and the outlet you can't see (on the bottom of the casting for the front brakes) comes out the bottom.

In all the admonishments I've had to "bench bleed" a new master cylinder, I'll note that it is actually impossible to do this since as soon as the lines or plugs for bench bleeders get removed, all the fluid would run out of the MC.

Interestingly, though, two of these MCs have a small port with a threaded plug. Any speculation as to their function? That's the technical question. Note that the two MCs with plugs have them in different places.

The question that almost sent this post to B.S. is: which one would you buy, and why?

p.s. I have the one on the bottom (generic)
OEM.jpg
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MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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rridge
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Re: OEM, OEM quality or value engineered?

Post by rridge » Sun Jun 16, 2019 9:50 pm

I simply don't buy unbranded parts unless there is no other alternative and used but tested parts are unavailable. This section has accumulated quite a few stories of problems with the fit and performance of unbranded master cylinders over the years.

Rebuilding a master cylinder is an alternative if seals are available and the bore is uncorroded. I've had corroded bores resleeved rather than install a mystery part.
Richard
'81 Turbo Spider
Rockville, MD
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MikeGreer
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Re: OEM, OEM quality or value engineered?

Post by MikeGreer » Sun Jun 16, 2019 11:18 pm

I wouldn't touch the bottom one, it's way too much work to install a pig in a poke. If they don't bother to get the details correct on the outside, how much effort do you think they put into the inside?
45 years with a spider, that's a long time
Restoring the '79 for the second time, you're never finished ;)
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friedman
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Re: OEM, OEM quality or value engineered?

Post by friedman » Mon Jun 17, 2019 7:52 am

I buy parts from our esteemed vendors. I assume they get plenty of customer feedback and would not knowingly sell crap parts.
Carl in Virginia
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Jefco
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Re: OEM, OEM quality or value engineered?

Post by Jefco » Mon Jun 17, 2019 1:19 pm

In other MCs, that little bolt has a pin on the inside to keep the pistons from popping out.
Looking at the manual, they call them 'stop bolts'.
Jeff
1986 Bertone X
1972 124 Sport Coupe (2L project)
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Re: OEM, OEM quality or value engineered?

Post by paulc » Mon Jun 17, 2019 3:41 pm

These look like what AR describe as being for a Volumex. Not sure that's what you have.
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Re: OEM, OEM quality or value engineered?

Post by miker » Mon Jun 17, 2019 5:50 pm

Yes, that's right. The odd thing is that the ones AR sell separately are different than the ones that come bundled with the Volumex booster. I just ordered the FTE-branded unit from Italy, it will be awhile before I know if this solves my problem. If it I notice a big change for the better, I'll send the original one back for inspection. This particular MC configuration is used on Volumex, but also Ritmo, and a bunch of pre-ABS Alfa Romeo cars as well.

This project has been kind of a pain, but a boon to my brake fluid manufacturer. The good news is the new MC swap will take very little time since I've gotten so much brake bleeding practice.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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oops, now what

Post by miker » Sun Jun 23, 2019 5:46 pm

So, take a closer look at the FTE master cylinder that I ordered from Italy, and see if you can spot the problem with using that one instead of the one on the bottom of the post.

When I got the generic one, I had to reuse the rubber inlet grommets from my original stock MC because the grommets on the generic one were too small (I.D.) for the right-angled inlets. No problem, but when I ordered the new FTE MC I also got some new grommets because it's clear from the photo that the I.D. of the supplied grommets is too small and I figured one reuse was enough.

What's less clear is that the machined inlet of the FTE cylinder is too small for the larger grommets. In other words, the original and generic MC can take different grommets to accommodate either inlet, but the FTE one can only take the smaller ID grommets, which by the way, are perfect for a top-mounted reservoir.

So it seems I have a few options: reinstall what I had on there, get this new MC machined out for larger grommets, use smaller inlets and some kind of hose adapter for the larger supply hoses, or....

There is a machined groove in the base of the inlet of the FTE unit that almost seems like it would capture the seating ring of the nylon nipple, but I can't find any example of an MC without a grommet.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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Re: OEM, OEM quality or value engineered?

Post by fiatfactory » Tue Jun 25, 2019 10:05 pm

Mike,

you do realise that these master cylinders also come with 10 x 1.25 thread pitch (lke volumex) but later Ritmo etc uses a 10 x 1.0 thread pitch... all with 22.2mm bore size.

SteveC
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miker
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Re: OEM, OEM quality or value engineered?

Post by miker » Tue Jun 25, 2019 10:50 pm

Yes, I did make the modification for 10x1.00 already. I installed a brake booster and 22.2mm diameter MC from one of our vendors that is kind of for a Volumex Spider (but it came as 10x1.00, not 10x1.25), but of course this same setup was also used on a bunch of other mid-late 80s+ Fiats. The brake line changes were a little challenging as it was my first time.

My problem is that this MC is suspect. I have bled it every way known to man and it still feels mushy. At the time I installed it, I also installed new 38mm rear calipers and I have the smallest piston Wilwood calipers on the front (from the Whoa brake kit).

When I checked around, I noticed that there seem to be two kinds of MCs in circulation for Fiats these days- cheap and cheaper. I decided to try to find something higher quality and using part numbers and so-called equivalents, found a made-in-Germany FTE MC that I had sent from Italy. It looks really nice, but the inlets are too small for the Spider inlet fittings (the ID of the inlet grommet is 8mm, and the machined opening is too small to accept a larger I.D. grommet). This MC was designed for an on-MC tank, as in the 130 twincam Ritmo.

Having spent $150 on this FTE MC, I have three options: sell it on Ebay and get another generic MC and hope my luck is better, use some 8mm brass barbed flex tubing joiners and hope that will seal in the grommets of the MC (and not pop out when I use 15PSI on the pressure bleeder) or find a plastic tank that can sit on top, eliminating the separate reservoir and all the hoses. The Ritmo "dogbone" tank is too big for sure, but https://www.amazon.com/dp/B004C3DV5C might work. These VW tanks seem to have 8mm diameter fittings on an 85mm center which I think would match the FTE MC.

I worry about the fit ... too close to the intake manifold and engine heat? What if the engine rocks too much and hits it (how much clearance do I need). I have a single-plane manifold but what about the IDF waffle manifold? And will I end up having to drain the brake fluid tank to take off an intake manifold? Are these reasons why I have never seen anyone do a booster + MC + integral tank on a Spider?

(edited...p.s. it looks like it would be hard to adjust the idle mix on the 36ADL)

Also, if anyone has a known great brand for a 22mm MC of the Ritmo style (with the tube encasing the pushrod as it comes out of the booster) with larger inlets, I'm all ears on that, too.
Last edited by miker on Tue Jun 25, 2019 11:31 pm, edited 1 time in total.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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