Brake Master Cylinders, OEM -vs- 2010 Aftermarket

Rupunzell

Rupunzell

Bernice Loui
The 74' needs to have it's brake master cylinder replaced after all these years. The current set of master cylinders appear to be OEM from when the exxe was made in 1974.

It was not too long ago when the replaced brake master cylinder in the LeMons racer decided to act weird and inconsistent. Another new aftermarket one went in and I took apart the problem master cylinder.

One look at the internals, proved that this aftermarket brake master is not what I'm willing to use as a replacement on the 74'

Found a NOS on evil-bay and took it apart to compare. The top exploded view of the brake master is a Fiat OEM, the one on the bottom is a current aftermarket brake master.

The design of the seals are completely different (oval edge rings stock OEM, -vs- Cup seals on the aftermarket) along with the spring and their spring rates. Note the cheap stamped parts and poor quality materials. The thin shafts used on the after market pistons are going to flex under pressure causing the seals to shift and rock under pressure.

Adding to all these problems, the stock OEM cylinder is 3/4" or about 19mm. The Aftermarket cylinder is 13/16" or about 20.5mm. This will result in lower effective braking force at the brake calipers for the same pedal force.

Due to the amount of shelf storage time on the NOS unit, the cylinder walls are a bit rusty rendering this cylinder not useable.

The current plan is to get a quote to have the cylinder sleeved in 304 stainless steel with a hydraulic sealant and sleeved cylinder honed to size. This will likely cost several times what the current aftermarket brake masters cost, but I'm not willing to use anything less than OEM or better and the adventure of changing master cylinders on the exxe is not anything that should be done every weekend..

Beyond that, brake safety and performance is not worth any cost savings.


Bernice

74%2520exxe%2520Brake%2520Masters%2520OEM%2520%2526%2520Aftermarket.jpg
 
This explains something

While doing a major brake job on one of my X19's a few years ago I replaced the master cylinder among several other things. When done the pedal effort had a noticable increase. I checked and rechecked everything except for removing the master cylinder. I suspected that the master cylinder may have been bigger by the way the brakes acted, that is heavy pedal effort along with less pedal travel. I guess it's time to remove and check the size. Great find.

Charlie
 
Great work, as always.
I went NOS 3 years ago and all is well. Kept the old one for possible rebuild or sleeving. Next time it goes out I'm thinking a nice sleeved one with OEM internals should make it out last the car.
 
Master cylinder

Tell ya' what...I spent all day yesterday replacing the master cylinder in my X. I think I can say I could happily live out the rest of my years never having to do that again! Yeesh!:nuts:
 
theXbomb said:
Tell ya' what...I spent all day yesterday replacing the master cylinder in my X. I think I can say I could happily live out the rest of my years never having to do that again! Yeesh!:nuts:
Click to expand...

Agree! I've done two sets now, luckily the ones on my current X were in good shape, the brake master was already sleeved with stainless :)

Bleeding wasn't very hard either after I discovered sucking on the bleed hose gets out the bigger bubbles... Didn't taste great, but worked a treat :)
 
Sleeving

I had a batch of six brake and clutch masters for my Scorpions and X1/9 sleeved in brass by a guy in Quincy, CA several years back. I've heard both pros and cons of using brass vs SS, but have been very happy with the results. They have been on the cars for about seven years with no issues. I should have done the slave cylinders too, as they don't last long if the car isn't drive frequently.
 
Me thinks this is one explanation for why so many folks replace their OEM masters and get far less service time from the replacement.

Certainly proper installation, clean fluid w/regular flushes will make things better. But we're starting the install with inferior components :-(
 
Called a cylinder sleeving shop today. Cost for installing a stainless steel sleeve is $120 with warranty. Not bad at all.

Had a long discussion with the shop owner about sleeving cylinders, why and who his customers are. Turns out, this is a very common procedure for vintage car restoration where brake cylinders cannot be obtained. His other customer base are car folks that have taken apart the new cylinder only to discover how awful the new cylinder is made. That is when they decide not to install knowing the new part will fail.

IMO, this is a result of off-shore manufacturing of so many car parts today. In the case of Fiat parts, the market will not willingly accept parts that cost more, in response manufactures and parts distribution respond by offering parts at a price the market is willing to pay. It is also possible manufactures and parts distribution is SO profit driven that only the lowest cost/ lowest quality parts are offered.. offering little to no choice on replacement parts.

Not too long ago, an after market clutch hose was ordered for my SAAB, when the part arrived it was of such low and de-contented quality that it had to be returned and there was no possible way that hose was going to be installed. The supplier told me they have sold some with few complaints.

To deal with this problem hose, a replacement made using Parker 919, stainless steel/teflon hose was made to order. The overall cost was not much different than two of the inferior quality part.

There is a balance here, if the market is willing to accept inferior and poor quality parts, then that is all that will be available. If car folks flat refuse inferior and poor quality parts and the manufactures of these parts come to the harsh realization the market will not accept these parts, then it is possible the manufactures will respond by improving their offering.

A significant aspect of this is knowing the low cost parts offered are of inferior / poor quality and the market is simply not willing to accept this..... and the market is willing to PAY for a significantly higher quality part.


Bernice



geekdaddy said:
Me thinks this is one explanation for why so many folks replace their OEM masters and get far less service time from the replacement.

Certainly proper installation, clean fluid w/regular flushes will make things better. But we're starting the install with inferior components :-(
Click to expand...
 
I'm guessing you may not want to "name call", but I think it's probably beneficial to know more details about the manufacturer of the New or reconditioned units that aren't working. That way at least we could say "avoid this brand".. .or are you saying that they all appear to come from a european manufacturer and are of same quality?

I generally go to NAPA for higher quality replacements for other cars (and Midwest for Fiat). NAPA lists a remanufactured master cylinder from Altrom Imports. Is the poor quality one an Altrom one?

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ATMP9049_0288979442
 
So after reading this....

I took apart my leaky Centric aftermarket master to check the innards.
In the spirit of full disclosure, I came to the conclusion that my master was leaking around the spouts after 9 months shortly after the frigid temps hit. The other seals were not leaking.

Photo (poor quality on dirty towel :sad:) below suggests that this seems to be a rebuilt OEM unit -- more like the top cylinder in the original post.

The inside of the cylinder appeared to be very smooth with no corrosion.

I tossed the rubber surrounding the spouts before photographing them -- they were both very loose (hence the leaking). Not sure what was wrong although the rubber seals around the spouts seemed to be breaking down with "residue" left behind. I was using fresh dot4 brake fluid with new EPDM reservoir lines so not sure what caused the seals to "loosen up." All the other o-rings/seals seemed ok.

 
YUCK! Talk about ruining a Beer Buz!

myexonenine said:
...Bleeding wasn't very hard either after I discovered sucking on the bleed hose :eek::wacko:gets out the bigger bubbles... Didn't taste great, but worked a treat :)
Click to expand...

I do a lot of one man work and brake jobs This is definitely the may to go.
http://www.ebay.com/itm/BRAKE-BLEED...Parts_Accessories&hash=item20ceb2625c&vxp=mtr
You can find them even cheaper at WholeSale Overstock Sales, all over the place.
Or you can go for real cheap. Shop a veterinary or medical supply store and get a "Horse Enema" syringe similar to this. http://www.ebay.com/itm/5pcs-Plasti...821?pt=LH_DefaultDomain_0&hash=item1c3187489d
Just stick it in the Bleed hose and SUCK all you want.
On this job, my hands got tired, doing all the pumping with the Fancy one, so I just stuck the syringe in the hose, instead.
This also cuts out the catch jar, meaning better control of hoses, thus leaks. I used a small Visegrip to pinch off the hose, between "SUCKS" and drained the old fluid into a catch can, through a coffee filter, to check for rust, rubber or other foreign objects. Once I got to the NEW Dot 3, just put it in a different catch can the same way for future re-use. :)
 
Suddenly I'm Glad

I spent the extra bucks for a Michelli NOS. Had it checked out by my resident SAE Tech BEFORE Installing.:headbang:

My biggest issue, so far, has been getting the old lines to reseal, just one LAST time.:wall:
 
Another Old FART, I mean FIAT Owner

Old Fiat Driver said:
While doing a major brake job on one of my X19's a few years ago I replaced the master cylinder among several other things. When done the pedal effort had a noticable increase. I checked and rechecked everything except for removing the master cylinder. I suspected that the master cylinder may have been bigger by the way the brakes acted, that is heavy pedal effort along with less pedal travel. I guess it's time to remove and check the size. Great find.

Charlie
Click to expand...

My Question Is Reliability. If the newer stuff last, I might opt for more responsive Pedal feel and Power when needed.

I REALLY, learned to drive in these cars. I learned early on, when faced with a traffic problem, the LAST thing i wanted to do was STOMP on the Brakes. Do that, the Fronts lock up and you're just along for the ride.:eek:
Better to keep my wits about me and steer out of it.

That saved my life the night I squeezed the last juice out of "The Lone Lemon",

around a telephone pole.
Instead of hitting it head on at 70 MPH, I had just enough traction left in the grass to pull the E-Brake, just as I made a hard left, swinging it around so that the brunt of the impact on the passenger side door, was taken by the Engine, instead of my Head.:eek:

No pix, but it was folded like a beer can around a broom handle.:eek::eek::eek:
Don't remember any of it, but I got out and walked 200 yards to the nearest light, knocked on the door for help at 2:00 AM, then walked back and was resting against the driver's door when someone came to get me.
30 years later, I still have little bits of glass in my forehead, to remind me just how close I came that night to my "Last Kiss" being a telephone pole.:sad:
 
Good info here. Im also pretty upset with the quality of new aftermarket stuff, for lots of cars. Rebuilds can always be questionable, so you get a questionable new or questionable rebuilt part. I cant stand it. For lots of british cars resleeving is a common practice. As long as we can still get replacement seals, I think its the way to go. $100 for an aftermarket, or $120 plus seals for a resleeve that will perform as the original? Yes please! I wonder if this is why the pedal effort in moms X always seemed excessive. Its got a replacement master and I bet its the wrong size.

Mark
 
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