Brake master cylinder

[Monty]

More evidence:

1988-90 LeMans WRONG
1989-93 LeMans RIGHT!

You wanted an 072-8250 not 072-8251 I'm afraid.

Dam, looks like the bore is also wrong on the ones Candles and I have purchased

I`ve just looked through my findings earlyer in this thread (see quote below) and the ones we ordered looked correct, so i`ve just re-checked RockAutos and they`ve seemed to off removed the BECK/ARNLEY Part # 0728751 from the list well at least it only cost £20

I've looked through RockAutos and it's possible these are what were looking for as the bore looks correct 7/8" = 22.22mm

1993 PONTIAC LEMANS SE 1.6L 1588cc 98cid L4 TBI (6) : Brake/Wheel Hub : Master Cylinder

BECK/ARNLEY Part # 0728751
2631 Stamped On Top Of Brake Booster [Wholesaler Closeout -- 30 Day Warranty] $88.99


RAYBESTOS Part # MC39869 {Professional Grade Bore Size=7/8" Number of Ports=4 Primary Outlet Size=M12x1 Secondary Outlet Size=M10x1}
Power Brakes $109.79


A-1 CARDONE Part # 112561 {[Master Cylinder] Reman.} $117.79


ACDELCO Part # 18M478 {#18030720}
CYLINDER,BRK MAS DURAST0P; 7/8 CYLINDER BORE-WITH POWER BRAKES $252.99


DORMAN Part # M39869 {First Stop}
w/Power Brakes; Bore = 7/8"
* Non-stock item--shipping delayed up to 2 business days $141.79

The other question is do the USA use the same thread pattern for the brake pipe conections

[GeoffSmith]

From the Bendix site, it looks like any of these are correct:

Code: Select all

AC-DELCO       174-812     [174-811]
AC-DELCO       18M478      [18M479]
AC-DELCO       18M555
AUTOSPECIALTY  M-13002     [M-13001]
AUTOSPECIALTY              [M-13003]
BECK/ARNLEY    072-8751‡   [072-8750†]
BECK/ARNLEY                [072-9025]
CARQUEST       E150607     [E150196]
CENTRIC        130.36002   [130.36001]
CONI-SEAL                  [MC251090]
EIS            E150607     [E150196]
FRICTION MASTER            [2361]
GENERAL MOTORS 3492362     [3492139]
GENERAL MOTORS             [3492361]
ITM            25-01609
LUCAS GIRLING  211526      [211525]
MIDAS                      [CM1895]
NAPA (BRAKE)   39869       [39870]
RAYBESTOS      MC-39869    [MC-39870]
WAGNER                     [F119270]

Square brackets indicates wrong one according to Bendix.
† indicates confirmed correct
‡ indicates confirmed wrong


It's unfortunate that you and Candles got the wrong one but at least now we know the reason why and it just wasn't a bum steer. You never know, you may be able to source some adapters.

[dapinky]

I'm totally lost now

Geoff, in the table above, you seem to list equivalents from a Bendix cross-reference......

Yet the Beck-Arnley number in that table is 072-8751, and in an earlier thread you mentioned that we need the 072-8750 model.

I'm not being a smart-arse critic (makes a change!), and i appreciate all the work that has gone into this enterprise, I just don't want anyone else to end up with the wrong bits.

PS
I would have thought that the fittings should be availlable in the US, either as a standard size or as a Pontiac part#. If we can get the male fittings, it will be easy to knock up a set of pipes, either full-length, or short runs to a 'standard' metric M10 fitting to enable a jointed union.

[Monty]

From the Bendix site, it looks like any of these are correct:

Code: Select all

BECK/ARNLEY    072-8751


That is the one i have

[GeoffSmith]

Yeah, it looks like the Bendix site may have some errors! I've added the 'wrong' list as well.

[Monty]

More evidence:

1988-90 LeMans WRONG
1989-93 LeMans RIGHT!

You wanted an 072-8250 not 072-8251 I'm afraid.

Dam, looks like the bore is also wrong on the ones Candles and I have purchased

Just an update,

The link geoff posted above was saying that the MBC 072-8251 i got from the USA was also the wrong bore, well i can confirm it is infact the correct bore and i`ve swaped the inners to my spare MBC from Pinky1


Candles what have you done about the BMC?

[surfboardfiller]

With all this careful work and patience, would it be worth sorting out an upgrade to the inadequate BMC?

[Candles]

Copped out: I've bought one of the pm something x-ref lucas parts above and fitted it. I need to progress my project or it'll never see the summer.

I'll keep the pontiac one and swap the internals if it was easy?

A local machine shop said they'd make up the nuts to convert it for about £25, as I cannot find them anywhere. M12 is the biggest I've seen and they are about M15.

Candles.

[Monty]

With all this careful work and patience, would it be worth sorting out an upgrade to the inadequate BMC?

Phil, it`s not easy to find a direct replacement but i did find one with a slightly larger bore from Rockauto`s but don`t know if it will fit If i can find a cheap one on the US ebay i`ll buy one to test.

What is the bore of the BMC (ie, 1-1/8" bore?)? Also what is the distance between the two bolt-holes? In other words, is it a GM standard "mounting-pattern" like this one? http://www.ssbrakes.com/products/detail ... (0%20-%200) Seems if we knew some of these figures we could go up in bore size yet still find a bolt-in BMC. Comparing bore & stroke of various units (ie, Bore = 0.7”, stroke = 41 mm movement) makes it easy to compute total fluid movement VS pedal travel.

Nitro's,

The stock bore is 22.2mm (7/8")

Found one on RockAuto's with a bigger bore 25.4mm (1") but don't know if it'll fit

1998 PONTIAC TRANS SPORT MONTANA 3.4L

http://www.rockauto.com/catalog/raframe ... 163k309450

[Monty]

I'll keep the pontiac one and swap the internals if it was easy?
.

Yep easy enough to do, it`s just a circlip hiding behind the seal

[Candles]

Cool. How did you check to see if the bore was worn/scored?

[Monty]

Cool. How did you check to see if the bore was worn/scored?

With one off these lol but oviously you can only check part way. But when i removed the old springs/seals they were spotless, no dirt or rust in sight. Personley i think it`s got to be very rare for these to leak and i`ve got a feeling that replacing them won`t solve our problem with the pedal feel which is down to the wilwoods and maybe an upgraded BMC is required

Be interested to know if it also solves your N/S front from locking up

[Elanlover]

Monty (or anyone else), did you get any further on the BMC with the larger bore possibly fitting our cars? I have to admit I'm pretty confused with all the part numbers flying around but I'm guessing the general consenus is a larger bore BMC with our fittings/fixings would be ideal.

[Elanlover]

Random Googling led me to this articlewhich would seem to substantiate the need for a larger bore BMC when larger calipers are fitted.

[Monty]

Monty (or anyone else), did you get any further on the BMC with the larger bore possibly fitting our cars? I have to admit I'm pretty confused with all the part numbers flying around but I'm guessing the general consenus is a larger bore BMC with our fittings/fixings would be ideal.

The only one i found (which i listed on this page) with a bigger bore is the one i`ve just quoted below but i don`t know if it will fit, it looks very similar except for the reserviour which might be able to swap with the stock one
We need someone on the state side to try and get one from the scrapyard to compare

With all this careful work and patience, would it be worth sorting out an upgrade to the inadequate BMC?

Phil, it's not easy to find a direct replacement but i did find one with a slightly larger bore from Rockauto's but don't know if it will fit If i can find a cheap one on the US ebay i'll buy one to test.

What is the bore of the BMC (ie, 1-1/8" bore?)? Also what is the distance between the two bolt-holes? In other words, is it a GM standard "mounting-pattern" like this one? http://www.ssbrakes.com/products/detail ... (0%20-%200) Seems if we knew some of these figures we could go up in bore size yet still find a bolt-in BMC. Comparing bore & stroke of various units (ie, Bore = 0.7”, stroke = 41 mm movement) makes it easy to compute total fluid movement VS pedal travel.

Nitro's,

The stock bore is 22.2mm (7/8")

Found one on RockAuto's with a bigger bore 25.4mm (1") but don't know if it'll fit

1998 PONTIAC TRANS SPORT MONTANA 3.4L

http://www.rockauto.com/catalog/raframe ... 163k309450

[Monty]

Just had a thought

Wonder if it`s possible to have the stock bored out to 1" as RockAuto`s has the a repair kit for the above BMC:?



http://www.rockauto.com/catalog/raframecatalog.php

1998 PONTIAC TRANS SPORT MONTANA 3.4L

part number TM122619

[Elanlover]

You'd think that'd be possible but would you want to take the chance that they'd get it right and not have leaks??? I sent an e-mail to Wilwood to ask if they have somethign that'd do the job (probably not but I thought I'd ask). May requie someone gettingon the phone with Dorman (or another manufacturer) and asking them for the spcs or walking them through what we need.

[Elanlover]

Ok, I took the plunge and, after a lot of calling around, managed to get an AC Delco tech guy on the phone. That BMC you sited with the 1 inch bore isn't quite right unforunately. Yes, they are metric fittings but they are both M10 x1. Based on your pic from earlier in this post we need one with an M10 and another with an M12. Correct? Too bad really.

[dapinky]

Now, this isn't something i am interested in, as my MBC is okay (touch wood), but there are specialists out there who will ream out brake cylinders and fit a stainless steel insert together with pistons & seals to match.

Haven't a clue on the prices either

(but they do work, 'cos i know a man who had one done on his Humber)

[Monty]

Ok, I took the plunge and, after a lot of calling around, managed to get an AC Delco tech guy on the phone. That BMC you sited with the 1 inch bore isn't quite right unforunately. Yes, they are metric fittings but they are both M10 x1. Based on your pic from earlier in this post we need one with an M10 and another with an M12. Correct? Too bad really.

If it came to the crunch brake pipes can always be made up, the main thing is does the bolt hole line up and the stock reservior fit

Like the sound of having the stock one reamed, may look in to this in the future