peteco said:
I just finished upgrading to the Hawk brakes: front rotors and pads, and rear pads. It took a while as I do brake jobs infrequently, so I have to relearn the finer points.
One finding was that the rear caliper pins were almost completely dry. I will add this to my maintenance plan.
Another finding was that all the brake pads were barely worn at 64,000 miles. I attribute this more to GM's design than to my easy driving habits. I think these "hard" pads lead to poor braking performance, which I hope the Hawk pads remedy.
The most difficult part of this job is bleeding the brakes to get a firm brake pedal. I have a Motiv pressure bleeder that works fine but it never quite got all the bubble out after bleeding 3 qts of fluid through the system. The pedal is not as firm as I would like. I have done the pad burnishing procedure that Hawk recommends. I will report my braking results after a few weeks on the road.
I also greased the hubs and will report my experience in the hub thread:
http://www.classbforum.com/phpBB2/viewt ... 265#p24265
Pete
2006 Roadtrek 210 Popular
I have always thought our brake pedal was a little soft and with a bit more travel than it should be, but it passes all the specs in the service manual, so it just may be a bit different than we are used to.
We did notice that the pedal seemed a bit softer after the brake change, but it also firmed up a bit after more use. It appears that those huge pads need a bunch of use to get fully flattened out to the rotor. After our trip though the mountain parkways, where we worked them very hard, they got a bit better yet.
A couple other things made incremental improvements. A good bleeding the first time we changed the brake fluid (before the brake change) got us a little better, as I got a bit of air out of the rears. I have never had great success with power bleeders, probably just me, because I would get a little air back in around the bleed screws when closing them. I was always by myself so I couldn't leave it pressured up well, and it was a cheap bleeder. I went back to the old pump, hold, open two person routine now and haven't had problems. I think part of it is if you do have any air, the first burst out of the bleeder when you crack it, will squirt differently than if there is not air, so you know when you are done. We didn't run the van when we did the manual way. I always use Dot4 Castrol LMA fluid, but that shouldn't have any effect on feel or travel.
I did change the Hydroboost fluid last year, and that did make a difference in feel and needed force, both for the better. I went with Redline synthetic power steering fluid, but they now recommend their D4 auto trans fluid, which I am going to go to this year. It has a bit higher viscosity at high temp than their ps fluid, and both are much better at high temp than the GM stuff. It is interesting that in cold areas like here in Mn, GM says to go to their thinner ps fluid, which would make it worse (they have some low temp issues with the standard ps fluid). The Redline is much thinner at cold temps, so there should be no issue with it. Even with the Redline ps fluid, I noticed an immediate reduction in pedal effort, as it is probably holding a little more pressure at the relief valve. The power steering pump also got a bit quieter. I would guess the ps fluid is running significantly cooler, also, based on touching the reservoir. From what I have read about Hydroboost, they need regular fluid changes, and should be done at or before the fluid starts to darken, if you want long life. I have no long term experience with them, so can't speak to that.
I think you will find the pedal to firm and raise for a while as the brakes fully seat. The bedding is more a concern with material transfer, but I would bet you still don't have 100% contact, I know I didn't even after about 6K miles (easy ones), so I just started using them harder :mrgreen: If you have been bleeding a bunch, you probably have all new fluid so that is good, but you may want to do a quick manual bleed to see if you get any air squirts. Changing the Hydroboost fluid to a good synthetic is a good idea, I think. I really like Redline for gears and gear type pumps, but I am sure there are other good choices also.
By the time you get to 10K it will probably be pretty nice, although the changes are so slow that you may not notice unless you think about it. I still wish ours had a bit higher pedal, but I like the feel and force, which does not change as they heat up like the stock pads did.