Upgrade to GSX DPCs . . . Bleed the whole system?

[DSMvroom]

Hi,

I've got the GSX brakes on my GST and it is time to bleed the system. Do I need to bleed all four corners or just the two fronts?

Obviously air got in to both the front lines, would there have been some air caught in the rear because of this?

Thanks!

 

[snowborder714]

I would definitely bleed all four corners. Depending on how low you let the fluid get in the master cylinder, air could've gotten into any of the hard lines. You just don't know where air is in the system. When I did this upgrade, I bled the system 2 times - one with cheap WalMart fluid to get out all the old, nasty stuff, and then once with Motul fluid. When you bleed the system, make sure to wipe out the master cylinder as crud just collects at the bottom of it and you don't want that stuff in your brake lines.

 

[Defiant]

http://www.dsmtuners.com/forums/showthread.php?p=1586255

 

[RamenPride]

I just bled the front two calipers.

 

[DirtyBirdRacing]

I agree with the second post and would bleed all 4 just to be sure.

Bill

 

[Todd TCE]

Just to be sure? Sure of what? If you don't know the answer...

If you replace one or even two calipers there's no need to bleed anything but the one side you've replaced. (or the set) Current cars have dual circuit systems that keep the front and rear brakes separate from one another. Most cars in fact have a split reservoir for safety. Should one run dry at least one end in theory will work.

The only reason for bleeding all four (aside from old fluid or just because) is if you for some foolish reason allow the reservoir to run dry while doing the bleeding process and that allows air to become ingested in the whole system. Not really very likely.

Replace the caliper, plumb it and open the bleeder. Put a drain pan under the caliper and let the fluid flow. When it's flowed about 2-3 reservoirs of fluid (that you keep topping off every five minutes or so) close the bleeders, and pump the pedal to seat the pads. Get a buddy to help squirt each three times and your done. Or...honestly...you could just open the bleeders again for a few minutes and close them without help, the air's gone.

 

[DSMvroom]

Thanks everyone for your input. Because I was uncertain and I needed the car up and running that day, I didn't take any chances and did bleed all four corners.

There was a small amount of air in the rear lines, but I suppose that was just air that made its way in over the years of ownership.

The reason I started the thread was because I thought I knew something to the effect of what Todd had posted in regards to separate circuits, but couldn't find any _useful_ links that spoke of it sufficiently when I searched.

Anyway, thanks again for your input. When all is said and done, I do recommend for everyone to do a full bleed when doing this upgrade, seeing as how I still managed to bleed some air out of the rear lines.

 

[DirtyBirdRacing]

Todd, I dont doubt your knowledge at all when it comes to brakes. Your kits from TCE are fantastic.

The reason I said what I did was I knew the 1g DSM's have an x-arrangement for there brake lines and I believe the 2g's do as well. Thus he could have air in the rears, like he did. Also, my feeling was what is the harm in bleeding all four you know.

I'm not trying to be a wise ass, just trying to defend what I posted.

Also, do you know why they switched newer cars to the front and rear grouped together as you said before?

Bill

 

[Todd TCE]

Sorry Bill didn't mean to sound as if I was wagging a finger at you as much as it came out.

You're right in that many cars do have a diagonal split to them vs others with front and rear mc port designs. My point was simply that regardless of the layout or design replacing one caliper or two won't require anything be bled beyond the part being replaced. Opening the RF for example will not introduce air into the LR. So long as the mc reservoir is not allowed to "suck air" by way of the RF being left open for 20min and run out of fluid there's no need to do more work than needed.

You're absolutely correct in that doing all four won't hurt anything. And given the vehicles age is probably the wiser choice.