# sleeving brake master instead of vacuum pump



## dtbaker (Jan 5, 2008)

planning my next conversion to start soon and rounding up the last few parts. One thing I have debated over is the whole vacuum pump for power brakes... but without vacuum the brakes are a little stiff for the average comfort of a young female driver (which I will have in the family soon).

One option is to find a new or salvage 'manual' brake master cylinder that has a slightly small bore than the stock OEM and replace.... I have not had a lot of luck finding an exact match for the three outlets on the 1997 Suzuki Swift, which means I'd have to do considerable re-plumbing of brakelines and hope balance front/rear was ok, etc...

Second option would be to find a shop that could sleeve down the existing master cyl... but this would require finding a rebuild rubber kit matching the new smaller diameter and fitting on the old pushrod. I am a little nervous about that since rebuild kits are listed by matching cylinders or vehicles, not bore diameters....

so.... I am asking the group. Has anyone 'sleeved down' a vacuum boosted brake master to eliminate the need for vacuum? how did you find matching dia rubber for rebuild?

or.... do ya'll think it would be easier in the long run to get a simple tandem master and re-plumb the outlets if I can figure out what the Suzuki is trying to do with the three outlets.


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## Duncan (Dec 8, 2008)

Hi DT

Get another "pedal box" from a scrappers - most cars use pendant (top mounted) pedals

and modify it and the pedal to move the pedal pivot point about 6mm downwards,

This will increase the leverage without messing with the hydraulics at all


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## dtbaker (Jan 5, 2008)

Duncan said:


> Hi DT
> 
> Get another "pedal box" from a scrappers - most cars use pendant (top mounted) pedals
> 
> ...


hhhmmm, I'll look to see how involved this would be. I would be concerned it would reduce the travel quite a bit. But it might just mean I get a little more pedal travel to fully actuate the brakes... which would be ok.


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## azdeltawye (Dec 30, 2008)

I think eliminating the vacuum pump is a bad idea.

The cost of implementing a Rube Goldberg-type of master cylinder will outweigh the cost of the vacuum pump when you consider the time spent and possible safety issues.

Check the thread below for a cheap and reliable oem vacuum pump. I got mine from http://www.car-part.com/ for less than $75.

http://www.diyelectriccar.com/forums/showthread.php?t=45605&highlight=audi


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## dtbaker (Jan 5, 2008)

azdeltawye said:


> Check the thread below for a cheap and reliable oem vacuum pump. I got mine from http://www.car-part.com/ for less than $75.


I took a look, and changing the pedal pivot would be a nightmare if possible at all... some clearance issues with steering column, and the mounting bracket would require a re-work that would take a fair amount of time. Not a good option in this car.

I poked around car-part.com a little, but the search required a make/year/model rather than just letting me look at available vacuum pumps. I am surprised you found one for just $75, and would love to look at the specs. Can you include a link to the actual unit you found? including vacuum switch and reservoir?

More I look at it, the easiest mod would be to bolt on a 'pedal extender' to lower the pedal pad and extend the lever arm... I think I could make it about an inch longer, but not sure how that would fit contact point with my foot even with my heel basically on the floormat. I might tryit though as it would be fairly easy to make it removable at least to test to see if it adds enough leverage and 'feels' right.


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## DavidDymaxion (Dec 1, 2008)

Apologies if you've already run down this list, but here are some other possibilities:


Maybe the GT version had larger calipers? If so that could be a bolt-in solution. Also a performance model of the car might also have larger diameter disks, which can help a bit.
Have you tried better brake pads? My gasser stops with about 1/2 the pedal force when I switched from cheapy generic pads to Hawk HPS pads.
If you change the pivot point, something to be careful about is firewall flex -- some firewalls might not be strong enough for the additional force possible. Have someone step hard on the brake while you watch the master cylinder -- you might be horrified by how much it moves already (I was on my car!).



dtbaker said:


> planning my next conversion to start soon and rounding up the last few parts. One thing I have debated over is the whole vacuum pump for power brakes... but without vacuum the brakes are a little stiff for the average comfort of a young female driver (which I will have in the family soon).
> 
> One option is to find a new or salvage 'manual' brake master cylinder that has a slightly small bore than the stock OEM and replace.... I have not had a lot of luck finding an exact match for the three outlets on the 1997 Suzuki Swift, which means I'd have to do considerable re-plumbing of brakelines and hope balance front/rear was ok, etc...
> 
> ...


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## dtbaker (Jan 5, 2008)

DavidDymaxion said:


> ...here are some other possibilities:
> 
> 
> Maybe the GT version had larger calipers? If so that could be a bolt-in solution. Also a performance model of the car might also have larger diameter disks, which can help a bit.


There is no 'performance' or GT version of the Swift/Metro I am aware of.  There also is no boosterless version, even in the early years, which I find astounding in a car that was so cheap, small, and light.




DavidDymaxion said:


> Have you tried better brake pads? My gasser stops with about 1/2 the pedal force when I switched from cheapy generic pads to Hawk HPS pads. I just went and looked at the Haw site.... they say they are sticky when cold, but bad news is that they do not list a compatible set of pads for Suzuki Swift or Geo Metro


hhhmmm, I haven't looked to see if there are significantly different compounds available. Are the Hawk HPS pads sticky right off the bat, or only at 'race temp' after warmed up?




DavidDymaxion said:


> If you change the pivot point, something to be careful about is firewall flex -- some firewalls might not be strong enough for the additional force possible. Have someone step hard on the brake while you watch the master cylinder -- you might be horrified by how much it moves already (I was on my car!).


I am NOT going to open that can of worms.... limited space above steering column etc make it look like that would be a way more involved and costly change than sticking with vacuum pump.


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## DavidDymaxion (Dec 1, 2008)

Hawk HPS = "High Performance Street."

They stop great cold and hot, they do not need to be heated up to work well like racing pads.


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## dtbaker (Jan 5, 2008)

DavidDymaxion said:


> Hawk HPS = "High Performance Street."
> 
> They stop great cold and hot, they do not need to be heated up to work well like racing pads.



sound great, and a little extra grab from pads may be all I need.

but they are not listing a compatible part number for Suzuki swift/ geo metro . ;( Are you familiar with any other sticky pads I can try to look up?


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## EVfun (Mar 14, 2010)

I think part number 8E0927317 (sometimes with an A through H at the end) will work for the VW vacuum pump. There are a couple on E-bay right now for less than $100. A google search for "VW Audi brake vacuum pump" (without the quotes) will turn up more information and places you can buy them new.

Here is an interesting paper about the VW Audi brake vacuum pump system with some info about the terminals on the pump and internal construction.


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## dtbaker (Jan 5, 2008)

EVfun said:


> I think part number 8E0927317 (sometimes with an A through H at the end) will work for the VW vacuum pump. There are a couple on E-bay right now for less than $100. A google search for "VW Audi brake vacuum pump" (without the quotes) will turn up more information and places you can buy them new.
> 
> Here is an interesting paper about the VW Audi brake vacuum pump system with some info about the terminals on the pump and internal construction.


Do you know if this thing has vacuum switch built in to shut off at some pre-set.... or is it just an alternative to the typical Gast or Thomas pumps?


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## DavidDymaxion (Dec 1, 2008)

A good key word is "autocross." Autocrossers do a single 30 to 60 second lap at a time, so need good braking when the pads are cold. A couple of autocross forums I perused said Hawks are best, but some folks like Carbotech AX6 and EBC Yellows, too.


dtbaker said:


> sound great, and a little extra grab from pads may be all I need.
> 
> but they are not listing a compatible part number for Suzuki swift/ geo metro . ;( Are you familiar with any other sticky pads I can try to look up?


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## dtbaker (Jan 5, 2008)

DavidDymaxion said:


> A good key word is "autocross." Autocrossers do a single 30 to 60 second lap at a time, so need good braking when the pads are cold. A couple of autocross forums I persused said Hawks are best, but some folks like Carbotech AX6 and EBC Yellows, too.



cool, I will go see what I can find for the Swift/Metro.... they'll laugh themselves silly.


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## Duncan (Dec 8, 2008)

_There is no 'performance' or GT version of the Swift/Metro I am aware of.

_Hi DT_,

_There are some pretty racy ones around here and they used to be very popular as sprint autocross cars back a few years ago 
May be worth looking under some its other names

http://en.wikipedia.org/wiki/Suzuki_Cultus


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## dtbaker (Jan 5, 2008)

Duncan said:


> _There is no 'performance' or GT version of the Swift/Metro I am aware of.
> 
> _Hi DT_,
> 
> ...


the Cultus (sedan) is very different than the Swift/Metro of the 90's. The later hatchback, after 2001 is very different as well....


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## azdeltawye (Dec 30, 2008)

dtbaker said:


> ...
> I poked around car-part.com a little, but the search required a make/year/model rather than just letting me look at available vacuum pumps. I am surprised you found one for just $75, and would love to look at the specs. Can you include a link to the actual unit you found? including vacuum switch and reservoir?....


A quick search for a MY2003 VW Beetle revealed vacuum pumps starting at $40. See link below. Make sure to specify the electric pump and not the mechanical pump used on the diesels.

http://www.car-part.com/cgi-bin/search.cgi?userSearch=int&userPID=1000&userLocation=All+States&userIMS=&userInterchange=BA%3EAF&userSide=&userDate=2003&userDate2=2003&dbModel=75.3.1.1&userModel=Volkswagen%20Beetle%2FBug&dbPart=372.1&userPart=Vacuum%20Pump&sessionID=200000000000000000394214056&userPreference=price&userIntSelect=83087&userUID=0&userBroker=&iKey=&userPage=2

I used two vacuum switches made by Omron in my setup, one to control the pump and one for a low vacuum alarm. The details and specs for the Omron switches are in the vacuum pump thread I mentioned before…

Some people use PVC pipe for the vacuum reservoir. I just used an old aluminum fire extinguisher tank. There are many different options availble...


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## mizlplix (May 1, 2011)

*Sleeving is the last resort.*

I am a lifelong race car guy. I even made my living wrenching race cars for a period in my life. Having said that, this is my opinion.


The pedal leverage solution is not always workable in a compact production car. 

Manual, non power brakes conversions are not always possible because of caliper design.

If you ignore what your master cylinder looks like and are capable of changing the tubing ends, change the master cylinder. Measure the mounting holes and pattern. Find anything with the same mount. Change the tubing ends to suit. 

You will need at least a bore size 1/8" smaller than yours now.


Your pedal travel will almost double and the feel will not be as rock hard, but it will lock the brakes if you have it right. If the caliper has too small if a piston area, (built for power assist) you can never get the right mc bore. In that case, when you get the mc bore small enough to have the required pressure, you run out of travel and have to pump them twice to get a normal pedal.

If you wanted to figure it mathematically, you can get formulas online. I don't.


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## piotrsko (Dec 9, 2007)

poking around: Summit has 2 section wildwood MC for $45 in 1/8 increments.

Mizlplix: Then how do the ricers put those god-awful chrome plated 4 puck abortions on the front?


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## nxp (Apr 6, 2011)

dtbaker said:


> the Cultus (sedan) is very different than the Swift/Metro of the 90's. The later hatchback, after 2001 is very different as well....


I'm sorry but I quite disagree. The Swift GT/Cultus hatchback existed on the EU/Japan markets in the 89-91 model years. I have personally been involved in a conversion of a Swift GS to GT spec with a motor swap and few other parts. Front brakes were different, but I don't remember the details - my job was mostly with the wiring/ECU.

If I were you I'd look on Ebay UK - that's where we got most of the parts. Dunno if Ebay in Japan is usable for this.


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## mizlplix (May 1, 2011)

No problems when going that way (to bigger calipers/retaining power booster and original M/C). A power assisted system has a lot of volume and easy pedal effort. It can cover up a host of sins. With a big bore M/C, we get a lot of extra fluid with a little pedal stroke and still have an easy pedal.

The trouble starts when you go from a high flow/powered system to a non powered system with the same big bore M/C. Lower system pressure, hard pedal, life sucks. 

Either change pedal leverage or change M/C to a smaller bore to recover our pressure. Then we have more pedal travel but high pressure is restored (using original calipers). 

Now we change out to a larger 4 piston caliper. We have easy pedal (high pressure) but we have to pump it twice or three times to push all 8 pistons out (due to the small M/C bore). If the reservoir does not empty, we will eventually have a nice brake pedal. (until we release it and it bleeds back into the M/C, and we must pump it like that for each stop).

To use those trick Giant, chrome 4 piston calipers with no power assist, it requires a different pedal set up. a longer stroke with a savage leverage ratio, to go with our original M/C which gives us our volume back. Pedal ratio gives us our pressure without a Giant Roid enhanced leg. Most street cars do not have room for such a pedal set up. (SO 99% you will find are power assisted)

Real racecars use two separate Master cylinders. Not connected hydraulically.
They have a *balance bar* between them that is adjustable for front/rear braking bias. You can also use different Bore sizes to suit as well as adjust the pedal leverage ratio. 

Speaking of chrome....Place two wrenches in the sun. One black and one chrome. After an hour you can hold the black one barely and the chrome one will make you cry for mommy. What do you think of their shiny calipers now?

ANY color paint is MUCH better than chrome or polished on calipers. Ditto for chromed rotors.( It Also screws up the friction index).....While I'm on a roll....Drilled rotors Their aid to cooling is small, but they DO act like a big file on the pads and guarantee rotor cracking in the first 2-3 cooling cycles.

Sorry (and I have not even had a beer yet) Miz


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## piotrsko (Dec 9, 2007)

Thanks for the info on Rice rockets. I wondered why some of them always flicked the brake lights. I failed to realize however that they MIGHT be actually that stoopid.

Don't recall using a balance bar on the 'Cuda, we used a proportioning block on a dual circuit MC which , at the time, was a radical new thought process. Yeah, I'm a Geezer.


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## mizlplix (May 1, 2011)

Yah, balance bar systems are common in roundy and road race cars. They allow the driver to alter the front/rear braking bias quickly to suit changing car and track conditions. 

I crewed for Salleen a while and all 3 cars used balance bars. the red knob was on the left of the steering column. It was nice for loosening up the car on corner entry or adding more rear brake if the fronts were getting over heated.

Indycars are the same exact deal, only more precision made.

I guess I'm a geezer now too, today is my 60th birthday.

Regards, Miz


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## DavidDymaxion (Dec 1, 2008)

Happy birthday and good stuff you posted.

You can get some pedal travel back in some cases by switching to braided lines (so the lines don't swell when you step hard on the brake), and by switching to Castrol SRF brake fluid. The CSRF stuff has very low compressibility, and binds up water so it can't boil and cause a soft pedal. A 3rd way, that I mentioned earlier, is to strengthen the firewall to eliminate flex from hard braking.

Even fresh off a fluid flush, I found SRF seems to give a higher and firmer pedal than competing racing brake fluids.


mizlplix said:


> No problems when going that way (to bigger calipers/retaining power booster and original M/C). A power assisted system has a lot of volume and easy pedal effort. It can cover up a host of sins. With a big bore M/C, we get a lot of extra fluid with a little pedal stroke and still have an easy pedal.
> 
> The trouble starts when you go from a high flow/powered system to a non powered system with the same big bore M/C. Lower system pressure, hard pedal, life sucks.
> 
> ...


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