DSM Big Brakes INFO

What is the 'Big Brake' upgrade?

In the '93 model year, Mitsubishi upgraded the front brakes on the DSM AWD models to the 2-piston calipers and larger rotors (10.8" / 275mm) from the non-turbo Dodge Stealth / Mitsubishi 3000GT models. These brakes have 22% more swept area than the previous years' single-piston caliper system and a sizable improvement in braking power.

Can I upgrade my car?

Owners of all '89-92 DSMs and '93+ non-AWD models (including 2G) can upgrade to 'Big Brakes'. '91-92 Galant VR-4s and all '93+ AWD cars come with 'Big Brakes' from the factory.

NOTE: Early '89's (before 4/1/89) had smaller front brakes which were upgraded during the model year run. All '90-92 FWD and 90 AWD share the same calipers. The calipers for the '93-94 turbo FWD models were upgraded to the larger, thicker single-piston caliper design of the 91-92 AWD cars.

What about the rear brakes? Can I install Stealth / 3000GT rear brakes too?

1G: No. The rears on those cars are very different. The parking brake is a separate drum brake setup on the inside of the rotor, instead of the DSM system with the parking brake integral to the rear caliper. Even if you could install them, you'd lose the parking brake and a minimal change, if not reduction, in stopping power due to the increased mass and decreased swept area (-16.5%) of the Stealth rotor.
2G: You already have it installed from the factory minus the vented rotors (except for rare early '95s).

Comparison	1G DSM	Stealth
Rotors	solid	vented
Diameter	265mm	265mm
Swept area (cm^2)	68.6	57.3
Weight	3.87kg	5.07kg
Parking Brake	Integral	Separate

What parts do I need to upgrade to 'Big Brakes'?

1G: You will need the 2-piston calipers, hub-to-caliper mounting brackets, shimming hardware, brake pads and rotors. (NOTE: some 95 AWDs also come with the banjo fittings, so make sure the calipers you get have the threaded fitting not the banjo bolt fitting, if transplanting to a 1G.)

2G FWD: Same as 1G, except that you if you get 2G AWD calipers that don't have banjo bolt fittings, you will need to replace the brake line with a custom SS line to fit the body and caliper. If you get 2G AWD calipers that use the banjo fitting at the caliper, I believe they will bolt onto the FWD, though I have heard reports that the banjo fittings may be different sizes.

What can I use as a donor car to get the parts from a salvage yard, or to reference when ordering new parts?

Any '93+ DSM AWD, '91+ non-turbo Dodge Stealth / Mitsu 3000GT, or '92-'96 Mitsu Diamante.

Do I need to cut, weld or fabricate in any way to install these brakes?

No, everything is bolt-on.

Do I need to get new brake dust shields to clear the larger rotors?

No, the existing dust shields will clear the bigger rotors (barely), and it avoids the major task of pulling the front hubs and drive shafts to replace them.

Can I use aftermarket pads, or do I need to buy them from the dealer to get the shimming hardware?

Most aftermarket pads and calipers do not come with shimming hardware, so you will need to search around to find it (Pep Boys, NAPA, et al). If you can't find the shims anywhere, you will have to buy factory pads to obtain them. Yes, those shimming clips are important for the life of your brakes (and you too!). Without them, you may have excessive clearance and the pads may rattle in the caliper, or become misaligned, possibly reducing brake effectiveness and unevenly wearing the rotor.

I don't want to buy used calipers / rotors from a salvage yard, or I can't find them anywhere. Where else can I get them?

Try any of the various aftermarket dealers, one of the dealerships that offer discounts, or your local auto parts store. They can sell you new rotors or new / rebuilt calipers, whatever you desire.

NOTE: Be sure that the calipers you are purchasing come with the hub mounting brackets. The calipers are useless otherwise since the brackets are not sold separately.

What about ordering a 'Big Brake' kit from one of the aftermarket vendors? Is it a good deal?

It depends...

Pro: All of the parts are together (no hunting around town necessary), the parts are new, the vendor may have a lower package price than if parts are purchased separately from different vendors, and technical support / warranty is usually available.

Con: The kits can be pricey, and you may not be able to alter the kit to your tastes (different pads, cross-drilled rotors, etc.). Shop around, as prices vary widely, depending on brands/types of rotors (Brembo, factory, cross-drilled, slotted, etc.), new vs. rebuilt calipers, and type of pads involved.

Will I need a new proportioning valve?

You don't HAVE to get one, but without it, the front brakes do a greater amount of work than with the stock setup. If you have ABS, it will be even more beneficial to get the proportioning valve to reduce the front brake bias, but it is not mandatory. Personal preference is the determining factor.

FYI, here's the different factory proportioning valves available. The higher the split point, the more front bias. Please note that ABS and non-ABS valves are not interchangeable due to different port configurations. A new proportioning valve costs about $40-70 from the dealer. If anyone has 2G data, please Email me with it and I'll update this table.

Split Points:

Year	FWD	AWD
90-91 All	4200	3700
90-91 All w/ABS	4200	3700
92-93 All, 94 NT	2500	3500
92 All, 93-94 NT w/ABS	2500	3500
94 T	???	???
93-94 T w/ABS	2500	3500
91-92 GVR4	N/A	5200
95-99	???	???

Can I upgrade my ABS-equipped DSM?

Yes, since the Stealth / 3kGT NTs use the same rotors whether ABS-equipped or not.

What about stainless steel lines? Should I replace the stock rubber ones while I'm doing the brakes?

On cars with well-aged rubber brake lines (i.e. 5+ years) the rubber starts to rot and get soft. This gives you spongy brakes. If your brake lines are more than 5 years old, replace them when you upgrade to 'Big Brakes', either with stainless lines or new factory rubber lines.

Are stainless braided brake lines worth it? Yes and no. Stainless brake lines are more expensive then stock ones and usually require a little dremel grinding to fit perfectly, but they will firm up the pedal feel, provide better brake feedback, available DOT approved, look good, and have no negative effects, even on ABS-equipped cars. Stainless lines are a worthy upgrade, but if you can't swallow the cost or the slight fitment work needed, installing new stock lines will still help brake feel and performance. It's an easy upgrade to install with along with your 'Big Brakes'.

What about SpeedBleeders? Do they really work? Are they worth installing while I am in there?

They really do work. A small, one-way check valve inside the bleeder body prevents fluid that you have bled from the caliper from returning. No more worries about accidentally sucking in air or old nasty fluid in between brake pedal pumps, and it becomes a one-person operation.

Just like stainless lines, SpeedBleeders are a trade-off of price and utility. For those who bleed brakes regularly, the added cost of ~$5/each is small given the ease with which you can bleed your brakes in a hurry if needed, like at a track event or AutoX.

For those who rarely change their brake fluid (less than yearly), it probably isn't worth the added expense.
Sizes are SB1010 (10mmx1.0) for nonBigBrake calipers (front and rear), and SB7100 (7mmx1.0) for the BigBrake calipers. However, put a boxend wrench on both the front and rear bleed screws and make sure of this, as I believe Apr 92-up cars use 7mm on the front and rear, whether they have BigBrakes or not.

What kind of brake fluid should I use?

Use good quality, fresh DOT 3, 4, or 5.1 fluid (not DOT 5) from a sealed container. There are many good brands out there, such as Castrol LMA, ATE Super Blue, and Ford Heavy Duty, among others. The DSM archives have many recommendations by other owners that will match your driving style.

I want to go all out! Can I bolt on the HUGE brakes from a Stealth / 3000GT Twin Turbo?

No, it is not a bolt-on proposition. If you just gotta have MONSTER brakes, there are number of aftermarket vendors now offering giant bolt-on brake upgrades for the DSMs with 12" - 13" rotors and all of the necessary hardware, calipers, etc., but be prepared to pay for them.

To graft the VR-4 TT brakes to the DSMs, the spindle from the TT has to be modified by a machine shop so as to utilize the stock T/E/L front shaft bearings and hubs, and the stock Brembo calipers must be ground to fit 17" wheels, since the caliper sides will rub against the wheel spokes. Manuel Go seems to be the expert on this, and it is a very difficult proposition.

NOTE: In 1994, Mitsu upgraded the Stealth / 3000GT VR-4 TT brakes to even larger rotors front and rear, and they will not clear the stock 17" '91-93 TT wheels or brake dust shields. Aftermarket 17" wheels or '94+ factory 18" wheels are necessary for clearance.

What about bigger brakes for '95+ 2G cars?

If you want really Big Brakes, here is some info from Paul Estevez:




These brakes are the track system sold by Baer for the 2G. In addition to the standard price for the track system (which is approximately $850 retail), I bought two other options: the zinc wash plating and the slotting, which were an additional $120 (approx) for a total of $970 retail.

You should be aware that zinc wash plating will wear off wherever the pads contact the rotors. But, the rotor hats and the rest of the rotor (that is, wherever the pads do NOT contact the rotor) still look like the rotor does in the picture. I decided against cross drilling per the recommendations of John Archer at Archer Racing, who told me cross drilling will invariably lead to premature rotor warping and/or cracking, neither of which is appealing. The calipers are PBR 2 piston calipers, which is the same caliper that came with the 90-95 Corvette ZR1. I am quite certain of this, as I checked the brakes on a 93' ZR1. The pads come pre-set in the calipers and are performance friction pads; I can't remember which compound. Baer does offer a variety of different optional compounds with the kit. You could call them and ask them to send you their catalog for all the information. The kit also includes stainless braided brake lines and all the hardware you will need to install the kit, along with barely adequate instructions.

The installation went smoothly, although you can forget about using your factory dust shield; I "dis-installed" mine with a hacksaw. The instructions also noted that there might be a small adjustment to a lower control arm on some cars, but my car didn't necessitate that. Maybe it has something to do with that recall on the 2G for the faulty control arm ? I have no idea. Anyway, I did do something stupid which I will share because I'm sure only 10-12 people are reading this anyway: I installed the left caliper on the right side and the right caliper on the left side. Don't laugh you bastards! The calipers are identical and it is assumed the individual(s) installing the brakes are NOT idiots and KNOW that a bleed nipple on a caliper should always point UP. Well, heheh, I guess I showed them who the idiot is... :\ You CAN NOT bleed the air out of a caliper if the nipple points down.

Besides the instructions are two very detailed sheets regarding proper break in procedure for both the rotors and the pads: Suffice it to say that if you just bought new rotors (or resurfaced the factory rotors for that matter) and replaced the pads and then proceeded to SLAM on the brakes during the following 5-10 days, you would reduce the effectiveness of the pads (for good) and you would certainly cause premature warping of the rotors. For this reason, I'm waiting two weeks to try a 130 to 60 brake test. The break in period is longer if you have zinc wash.

I remember a post some time ago, from someone saying they knew someone else with fancy 13" rotors and 4 piston calipers and those fancy rotors were already warped and those fancy calipers didn't stop his car any faster than 93' and up AWD brakes on the street. Well, I wonder if that someone else bothered to properly "season the rotors" and "bed" the pads. <---fancy Baer Racing terminology I still don't understand, but basically mean break-in.

I could lock up my tires (don't have ABS) with my stock brakes, so I'm sure these new brakes won't stop my car any faster in city driving. But, it is my expectation that these brakes WILL provide a real advantage in repeated high speed highway braking where my factory brakes would fade. I also expect these brakes to perform well at road courses, like maybe Road Atlanta if I ever strike up enough courage to meet Gary Selph :) Besides the "wow, those things are big" factor, these are the only reasons I bought these brakes. If I never had any intention of track racing, and I just wanted more grabbing power from my brakes, I would have bought the MUCH cheaper 93' and up AWD upgrade.

Speaking of price, you should know that Baer sells the kit to almost all the vendors now. I bought my kit from Speedster Racing and I paid substantially less than retail for them.

Because the Baer kit is a little more uncommon an upgrade, I don't think a VFAQ is worth the effort.

Credits - thanks to all who contributed

• Kyle Zingg - Author/Compiler
• Dan Hurwitz
• Jeff Yip
• Sean Samblanet
• Rob Pavsner
• Eddie@Del-Car wrecking, Westerville, OH
• Manuel S. Go, Jr
• Kyle Munz ~bluegsx
• Mark Pilon
• John E Werner
• Jeff Thompson
• Mr. Luis Haddock
• Steve not@ DSS
• Paul Estevez