Cloud9...68

I have a 968 with a set of 944 Turbo S calipers front and rear that the previous owner installed (along with stainless braided lines). I use a Motive pressure bleeder, and while my results haven't been horrible, the pedal is always a little soft in the car, so I think I'm missing something in the bleeding process. I start at the wheel farthest from the master cylinder (so the right rear), and move progressively closer each step. Each caliper has two bleed screws, and I bleed the outer one first, then the inner. Is there something I'm missing? Do I have to do something within the ABS system? Any tips or tricks? I don't have this problem with any of my other cars. Thanks.

jmj951

With stainless steel braided lines, you should have a very firm pedal.

It helps if the brake fluid is really warm, and you may have to beat the calipers repeatedly with a rubber mallet to get more of the air out.

Also FYI, if any of your rotors are even the slightest bit warped, they will push the pads away in the course of driving and create more pedal travel. If you can get the pedal really firm when parked, but then you get a little travel after driving, you might want to check the runout.

Crazy Eddie

How much of the system did you bleed ?
When I did mine, I also changed the Master and Slave cylinder, so I had to bleed it at the slave location near the stater.
I also used the Motive, but at the calipers bleed screws, I used the Mityvac as well..
It's possible, if you bleed the whole system that you have air bubbles at the line before the slave ... ??
It's a stupid design if you ask me, but what do I know
Regards
Ed

raleighBahn

I do mine with Motive bleeder and have great pedal. Nothing special - just make sure there is plenty of new fluid and it doesn't run out. Don't have to do the clutch every time. Note: no pedal pumping required.

Cloud9...68

Thanks for the responses. A mechanic who knows these cars pretty well once told me the getting all the air out of the system is not straightforward - something to do with the plumbing for the ABS, iirc, but it was a long time ago. As I said, my pedal isn't terribly mushy, but I know it could be firmer. I'll be real careful when I change out the brake fluid this weekend.

kevincnc

I just did the brakes on my '89 Turbo and completely purged the 25 year old brake fluid from all the lines using a cobbled together vacuum bleeder. It was nice to see the old brown stuff gone and the new fluid running through. I'm no brake expert, but maybe you have air trapped somewhere in the lines if you haven't completely purged them. Mine are solid as a rock with the original non-braided lines.

mj951

As mentioned, you may want to bleed the clutch slave. Not required with each bleed but if it hasn't been done in a while it will be worth the hassle. It's the shortest line so last to be bled.

gpr8er

The Motive is great for a flushing of the entire system. I have one and use it on occasion, but the best way to get a solid pedal is the old school person in the driver seat pump and hold and crack the bleeder with a hose in a small bottle. Use a clear piece of hose and watch the air go through the hose. Start at the right rear.

67King

+1. I actually do both when I drain and flush (once per year). Hook up the Motive, pump it up, crack open the bleed screws (into a pair of Genesis bleeder bottles), and pump the pedal. You can watch teh level in the Motive from the driver's seat, so you don't have to worry about getting air back in. But you can move a LOT more fluid a LOT more quickly, drastically reducing the likelihood of trapped bubbles, if you do it like that.

User 52121

So on my car - I've found that the Motive works great for 90%. I usually then go and do the old-school 2-man pedal pump bleed method to get the pedal extra firm. My car is also NOT an ABS car.

With ABS... I'm hit or miss. My old GTI, I could *never* get the air out. Always wound up taking it to the dealer and having them bleed it (have a good friend who is a writer so it was easy). On my truck, the only way I've had any success with a firm pedal was to use a MityVac on the bleed nipple and suck the fluid out. Using the Motive and the pedal-pump method never got any of the air out.

raleighBahn

Mine has ABS and no issue with Motive - last time I did it was a couple of days before HPDE at VIR and the pedal was great. I will note that i load the motive with more than 1 liter of ATE gold. One liter is the precise amount needed, but my eyes aren't good enough to notice the exact moment when old turns to new, so i load in two liters. Therefore, each caliper is well bled. The reasoning being an extra $15 is no problem considering I'm about to ask the brakes to save me at the track for two days

67King

I used to do that, but the fluid mixes, and there is no definitive "old/new" point. However, removing the old with a turkey baster before you introduce the new will help. Ever since I lost brakes going into 1 at Road Atlanta, and I now not only drain entierly, but also on the advice of Chris Smith (www.chrissmithracing.net - great guy!) blow compressed air through the lines to be sure I get any potential stuff out.

I also use brake fluid that is sold in 500ml bottles, rather than the 1L stuff. Usually takes a little more than 1L to get a good fill if you do the clutch at the same time, and I don't have a whole liter lying around that has been open to the atmosphere.

catamount

I hear you on the extra brake fluid in the Motive. $15 is cheap insurance when we are talking about the one system on the car that our life absolutely depends upon working flawlessly!

BTW, all these comments assume one thing, that there's nothing wrong with the master cylinder. I currently have a slightly soft pedal even after installing new pads and fluid and properly bleeding the system. My uber tech has determined that there is an ever so slight leak in the MC that's causing this issue. So, we'll be dealing with that in short order.

Crazy Eddie

Sometimes, when that master cylinder starts to leak, it will show up dripping inside the car, near the break pedal. Check you car mat or carpet ...
Like I mentioned in the beginning, you should try to bleed the slave ...
Occasionally, that can be the trouble spot ... ??

Cloud9...68

Well, I went ahead and replaced the master cylinder with a new one, and replaced the brake fluid with Wilwood Series 600 high temp racing fluid (as the car is primarily a track car). After filling up the reservoir with fresh fluid, I attached my Motive pressure bleeder, and first bled the maskter cylinder. Then I bled both calipers simultaneously on the right rear caliper, then bled the MC again. Then I moved to the right rar caliper, then the right front, and finally the left front, and then bled the MC one last time. Result: About the same as before - no worse, but no better, either. I use the same basic method to bleed the brakes of the oher cars in the family, and always end up with a nice, firm pedal.

The brakes work fine - there's just a disconcerting amout of initial squish when I first press the pedal. It does when when the car is at rest, without the engine running, and when blasting around the track, so temperature isn't a factor. There are no leaks anywhere, and fluid flowed at a good rate from each caliper and MC bleed fitting. Any other ideas why I'm not getting a firmer pedal? Could it be the booster somehow? Thanks.