How To: 929 Brake Master Cylinder and Booster Install
10-17-09, 06:03 PM
#1
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How To: 929 Brake Master Cylinder and Booster Install
The 1991-1996 Mazda 929 with ABS came equipped with a 1" master cylinder and the booster bolts right up to the FC firewall, making this a fairly easy swap. The increased size of the master cylinder will give you pedal with less movement and by using the 929 booster the pedal effort will not be increased. The ABS equipped 929 MC requires a slight plumbing change when used on non-ABS FCs. I don’t know about size the non-ABS 929 MC or if it requires plumbing changes too, but they are less common anyway. If you have any experience with this, please post it up, as this might be an easier way to go. The size of the MC should be cast into it, look for a "1" on it somewhere.
I used the MC and booster from a 1992 929 with ABS. The guys at the junkyard indicated that in order to get it out, the engine has to be pulled, but with 3½ hours of time and effort one person did it with the engine in place, so keep that in mind if you want to pull it yourself.
Make sure you get the banjo fitting on the front of the master cylinder and you’ll also need a 3 way tee which can be found at the rear axle where the single rear line splits off to the calipers. These parts are available new from the dealer and don’t cost very much, part numbers: W023-43-504 (banjo), W023-43-505 (banjo bolt), 99562-1000 (crush washers, 2 needed), FB01-45-29A (tee). The M10x1.0 45 degree SAE double flare tube nuts for standard 3/16" brake line should be available through local auto parts stores quite cheaply, so do yourself a favor and get new ones. Do not undertake this work if you don’t know what you’re doing, brake failures can kill. Be sure to use proper double flares and check your work thoroughly before driving the car.
For the basic removal and install procedure, consult the FSM or the Haynes manual, there’s really no point in me repeating it as its pretty simple stuff really. I will only cover the modifications and changes needed to make this work on a non-ABS FC. The modifications and parts swaps required are simple and easy:
-You must swap the clevis from the stock booster pushrod to the 929 booster in order to fit over the FC brake pedal. Be sure to properly adjust the pedal after completing the job, this is an important step for the feel and safety of the brakes.
-The connector on the brake fluid level sensor is different, simply swap the FC one into the 929 reservoir (no fluid will leak).
-The stock brake bias valve and bracket must be removed and swapped over to the 929 MC. This requires some trimming because the bracket won’t fit around the back of the 929 MC, so cut it off so that only the passenger side nut is holding it on.
-Carefully bend the stock front brake lines away from the MC and connect them into the tee. Add a short length of brake line from the tee to the front banjo fitting on the 929 MC. Alternatively, get 2 banjo fittings and a double banjo bolt or a double banjo fitting and connect the lines directly to the port, bending them to suit.
-The vacuum nipple is on the opposite side of the booster, so this requires a different hose to make it work. I used a length of 15/32" hose and cut the check valve out of the stock hose and clamped it in place in the new hose. You will need to use some worm or similar clamps on the hose to get it to seal. You can also elect to trim the hard line to make it less obvious. Make sure the hose doesn’t collapse under the vacuum while the engine’s running.
Other than that it’s as straightforward as putting the stock booster/MC back in.
I ended up doing my plumbing differently as I was plumbing in an in-car adjustable brake bias valve at the same time, so I removed the stock bias valve and re-routed some of the lines in order to have a cleaner install with fewer junction points.
As for the time and cost to do this job, I’d say that one should be able to do this in under an afternoon if all you do is change the MC/booster. As for the cost, you can probably find an MC and booster for about $100 at a wrecking yard; check www.car-part.com for a list of ones that have one (they’ll ship if none are close). The only other costs are tools, tubing, brake fluid and assorted small parts for making the plumbing changes which might run you another $150 at the most.
The difference between the stock brakes and the 929 MC and booster is like night and day. The pedal effort is about the same, but the travel is much reduced, giving a very high, firm pedal with very good feel and modulation. I’ve only driven it for a short while now, but I definitely feel that it’s well worth the small amount of time, money and effort to do this modification. While I did make some other changes while doing the installation, I highly doubt that any of them had any significant impact on feel. I’ll be sure to report back at some point once I’ve gotten some track time with it.
Picutres are of the stock S5 NA (left) booster and master cylinder compared to the 929 unit (right). The last one is of the unit in the car, but before I finished. I'll try to get some more installed pictures later if anyone wants.
I used the MC and booster from a 1992 929 with ABS. The guys at the junkyard indicated that in order to get it out, the engine has to be pulled, but with 3½ hours of time and effort one person did it with the engine in place, so keep that in mind if you want to pull it yourself.
Make sure you get the banjo fitting on the front of the master cylinder and you’ll also need a 3 way tee which can be found at the rear axle where the single rear line splits off to the calipers. These parts are available new from the dealer and don’t cost very much, part numbers: W023-43-504 (banjo), W023-43-505 (banjo bolt), 99562-1000 (crush washers, 2 needed), FB01-45-29A (tee). The M10x1.0 45 degree SAE double flare tube nuts for standard 3/16" brake line should be available through local auto parts stores quite cheaply, so do yourself a favor and get new ones. Do not undertake this work if you don’t know what you’re doing, brake failures can kill. Be sure to use proper double flares and check your work thoroughly before driving the car.
For the basic removal and install procedure, consult the FSM or the Haynes manual, there’s really no point in me repeating it as its pretty simple stuff really. I will only cover the modifications and changes needed to make this work on a non-ABS FC. The modifications and parts swaps required are simple and easy:
-You must swap the clevis from the stock booster pushrod to the 929 booster in order to fit over the FC brake pedal. Be sure to properly adjust the pedal after completing the job, this is an important step for the feel and safety of the brakes.
-The connector on the brake fluid level sensor is different, simply swap the FC one into the 929 reservoir (no fluid will leak).
-The stock brake bias valve and bracket must be removed and swapped over to the 929 MC. This requires some trimming because the bracket won’t fit around the back of the 929 MC, so cut it off so that only the passenger side nut is holding it on.
-Carefully bend the stock front brake lines away from the MC and connect them into the tee. Add a short length of brake line from the tee to the front banjo fitting on the 929 MC. Alternatively, get 2 banjo fittings and a double banjo bolt or a double banjo fitting and connect the lines directly to the port, bending them to suit.
-The vacuum nipple is on the opposite side of the booster, so this requires a different hose to make it work. I used a length of 15/32" hose and cut the check valve out of the stock hose and clamped it in place in the new hose. You will need to use some worm or similar clamps on the hose to get it to seal. You can also elect to trim the hard line to make it less obvious. Make sure the hose doesn’t collapse under the vacuum while the engine’s running.
Other than that it’s as straightforward as putting the stock booster/MC back in.
I ended up doing my plumbing differently as I was plumbing in an in-car adjustable brake bias valve at the same time, so I removed the stock bias valve and re-routed some of the lines in order to have a cleaner install with fewer junction points.
As for the time and cost to do this job, I’d say that one should be able to do this in under an afternoon if all you do is change the MC/booster. As for the cost, you can probably find an MC and booster for about $100 at a wrecking yard; check www.car-part.com for a list of ones that have one (they’ll ship if none are close). The only other costs are tools, tubing, brake fluid and assorted small parts for making the plumbing changes which might run you another $150 at the most.
The difference between the stock brakes and the 929 MC and booster is like night and day. The pedal effort is about the same, but the travel is much reduced, giving a very high, firm pedal with very good feel and modulation. I’ve only driven it for a short while now, but I definitely feel that it’s well worth the small amount of time, money and effort to do this modification. While I did make some other changes while doing the installation, I highly doubt that any of them had any significant impact on feel. I’ll be sure to report back at some point once I’ve gotten some track time with it.
Picutres are of the stock S5 NA (left) booster and master cylinder compared to the 929 unit (right). The last one is of the unit in the car, but before I finished. I'll try to get some more installed pictures later if anyone wants.
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mr_vaughn (04-03-22)
10-17-09, 06:15 PM
#2
Nice.
For those non-racers out there who won't be plumbing in the adjustable bias valve, the proportioning valve from the 929 will work quite nicely.
Unlike the stock second gen prop valve, the 929 unit uses residual bleed back valves that help with pedal firmness.
I've run mine both ways (with/without the bleed back valves) and prefer it with, although that will come down to personal preference...the difference is noticable but not night and day.
For those non-racers out there who won't be plumbing in the adjustable bias valve, the proportioning valve from the 929 will work quite nicely.
Unlike the stock second gen prop valve, the 929 unit uses residual bleed back valves that help with pedal firmness.
I've run mine both ways (with/without the bleed back valves) and prefer it with, although that will come down to personal preference...the difference is noticable but not night and day.
10-17-09, 10:39 PM
#4
Through the latter part of the summer and into early fall I spent a lot of time in junkyards pulling boosters and master cylinders (I'm the poor sap referred to who spent 3 1/2 hours pulling the 929 set up).
All six units I pulled and installed worked perfectly.
I'd say that chances of a junkyard part working well are pretty good and the prices are obviously much better than reman parts from a store.
In my experience, boosters hardly ever fail. Just look for one that has no obvious dents and fluid leaks (from the master cylinder).
If your junkyard MC is bad just get a kit and rebuild it.
All six units I pulled and installed worked perfectly.
I'd say that chances of a junkyard part working well are pretty good and the prices are obviously much better than reman parts from a store.
In my experience, boosters hardly ever fail. Just look for one that has no obvious dents and fluid leaks (from the master cylinder).
If your junkyard MC is bad just get a kit and rebuild it.
10-18-09, 02:24 PM
#5
I wish I was driving!
http://www.summitracing.com/parts/WIL-260-4893/
This one also fits, is reasonably priced, aluminum body, and 1-1/16" bore. It bolts on and has prefect clearance to the actuator rod when adjusted to the fully retracted position.
The installation problem with this is that the outlet ports face the wrong way, and the outlet used for the rear brakes (the front-most fitting, outlet 'B') points directly into the passenger side shock tower. My solution to this was to tap the included fitting to NPT and use a 90 degree adapter. Even so, the shock tower had to be slightly massaged with a ball-pein.
This one also fits, is reasonably priced, aluminum body, and 1-1/16" bore. It bolts on and has prefect clearance to the actuator rod when adjusted to the fully retracted position.
The installation problem with this is that the outlet ports face the wrong way, and the outlet used for the rear brakes (the front-most fitting, outlet 'B') points directly into the passenger side shock tower. My solution to this was to tap the included fitting to NPT and use a 90 degree adapter. Even so, the shock tower had to be slightly massaged with a ball-pein.
10-18-09, 02:49 PM
#6
Rotors? What Are Those?
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^^^ will the above attach to the factory Brake Booster or to the 929 model?
and does this entire swap require to change the booster from the 929 model or keep the FC model?
Thanks
TwEaK
and does this entire swap require to change the booster from the 929 model or keep the FC model?
Thanks
TwEaK
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10-18-09, 03:11 PM
#8
I wish I was driving!
10-18-09, 08:55 PM
#9
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Thread Starter
Keep in mind though that with a much bigger MC on the stock booster, you'll have a harder pedal, as in it takes a lot more effort to acheive the same braking force. This should be in proportion to the difference in area of the MC piston. By using the 929 MC and booster, the effort won't increase.
10-19-09, 06:55 AM
#10
Mounting the Subaru 1 1/16" MC on the stock NA booster gives a very deceptive pedal feel...extremely shortened travel and very firm feel but lousy stopping power.
Sitting in the driveway after bleeding the system, you'll think you've really made an improvement but the amount of leg required to actually stop is disappointing.
Light pedal application will seem fine- and for normal street driving the brakes will feel great- but if you need to stop right now! the amount of force needed is excessive.
You could probably adapt but why bother?
Another real advantage to acquiring a matched booster/MC is that you don't have to set the booster pushrod length.
Although it's not terribly hard to do, it is a fairly critical adjustment and can be finicky, so why go through it if you needn't?
Finally...when installing any new booster, pay careful attention to the pedal>booster pushrod length.
Measure your stocker from the booster mounting flange to the clevis hole center and set your new one up to be slightly shorter- 1/8" should do.
This will result in a bit of slop as you initially apply the pedal but drive it a bit making several stops (they need not be hard stops)...4-5 miles will be fine.
Then you can loosen the locknut and turn the shaft to lengthen the rod (yeah, you have to be a bit of a contortionist, but it's not that bad) and retest.
You're doing this because as the system heats up, if the rod is too long your brakes will begin to drag and ultimately lock solid.
This happened to me only once when I installed the 929 setup and I misdiagnosed the problem as being related to the residual pressure valves on the proportioning unit.
After gutting these valves the problem remained and I finally found the real cause...too much preload on the booster from the pedal.
I found another set of residual valves, reinstalled them and the problem didn't return, it was the pedal rod all along.
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Dan Unk (02-03-20)
10-23-09, 03:46 PM
#11
Through the latter part of the summer and into early fall I spent a lot of time in junkyards pulling boosters and master cylinders (I'm the poor sap referred to who spent 3 1/2 hours pulling the 929 set up).
All six units I pulled and installed worked perfectly.
I'd say that chances of a junkyard part working well are pretty good and the prices are obviously much better than reman parts from a store.
In my experience, boosters hardly ever fail. Just look for one that has no obvious dents and fluid leaks (from the master cylinder).
If your junkyard MC is bad just get a kit and rebuild it.
All six units I pulled and installed worked perfectly.
I'd say that chances of a junkyard part working well are pretty good and the prices are obviously much better than reman parts from a store.
In my experience, boosters hardly ever fail. Just look for one that has no obvious dents and fluid leaks (from the master cylinder).
If your junkyard MC is bad just get a kit and rebuild it.
Last edited by pistones; 10-23-09 at 03:47 PM. Reason: wrong quote
10-23-09, 04:21 PM
#12
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Thread Starter
I'm not sure since I went to a yard where they pull it, but I gather the engine's in the way and it has to be somewhat disassembled or even removed in order to get the booster out. Search for clokker's post a while back about it, it's described in detail.
The track test will have to wait, the car won't start, so I'm off to the track in my Focus...
The track test will have to wait, the car won't start, so I'm off to the track in my Focus...
10-23-09, 05:43 PM
#13
The master cylinder and proportioning valve come off with no problem...the booster, not so much.
It can't be pulled all the way off the firewall far enough to clear the mounting studs before it hits the DS valve cover.
Very close, but not all the way.
Pulling the valve cover requires removing the upper intake manifold.
Among other things.
It's a lot of work with handtools in less than ideal conditions.
One side benefit...
The 929 uses some beautiful bolts to hold the intake manifold on and turns out, they are perfect to mount our waterpump/housing with.
Make sure you take a look at them while you're in there.
10-24-09, 10:54 AM
#15
You won't need anything exotic, I did it with my minimal "junkyard" toolbox.
If you grab the proportioning valve and decide to use the stocker instead, let me know (or if there are two 929's there, grab the second valve...I'm in the market for another...).
If you grab the proportioning valve and decide to use the stocker instead, let me know (or if there are two 929's there, grab the second valve...I'm in the market for another...).
10-27-09, 08:17 AM
#16
Wow i cant believe it took you so long to remove it. I just dropped the subframe bolts and it took me literally 20 minutes to remove. The only tools needed was a 21mm socket and wrench, 10mm flare nut wrench and a 1/4" metric socket set and a pair of pliers.
Did you mean the prop valve attached to the master or the one by the abs? I didnt remove the one by the abs.
I also had a major FAIL moment! I left my snap on impact gun by the car and forgot it. By the time i realized it was gone
Did you mean the prop valve attached to the master or the one by the abs? I didnt remove the one by the abs.
I also had a major FAIL moment! I left my snap on impact gun by the car and forgot it. By the time i realized it was gone
10-27-09, 03:21 PM
#18
luckily for me all the cars were mounted on a set of steel wheels welded to the body, thats how they set up all the cars. out of 100 acres there was only one 929!
yea i got that proportioning valve, i will let you know if i end up using it.
i also found an uncracked dash out of an 88 E30 vert. $13.40! score for me. i don't even have the car yet but i figured it was in great shape and cheap.
so total spent on parts
master cylinder 12.00
brake booster 17.00
dash pad 14.00
about $45 with tax!
i love that place.
yea i got that proportioning valve, i will let you know if i end up using it.
i also found an uncracked dash out of an 88 E30 vert. $13.40! score for me. i don't even have the car yet but i figured it was in great shape and cheap.
so total spent on parts
master cylinder 12.00
brake booster 17.00
dash pad 14.00
about $45 with tax!
i love that place.
10-27-09, 03:31 PM
#19
luckily for me all the cars were mounted on a set of steel wheels welded to the body, thats how they set up all the cars. out of 100 acres there was only one 929!
yea i got that proportioning valve, i will let you know if i end up using it.
i also found an uncracked dash out of an 88 E30 vert. $13.40! score for me. i don't even have the car yet but i figured it was in great shape and cheap.
so total spent on parts
master cylinder 12.00
brake booster 17.00
dash pad 14.00
about $45 with tax!
i love that place.
yea i got that proportioning valve, i will let you know if i end up using it.
i also found an uncracked dash out of an 88 E30 vert. $13.40! score for me. i don't even have the car yet but i figured it was in great shape and cheap.
so total spent on parts
master cylinder 12.00
brake booster 17.00
dash pad 14.00
about $45 with tax!
i love that place.
