My new '67 Firebird got delivered today (pics to follow when weather clears) and had kind of a scary experience. I was driving it home from a buddies house, doing about 50 mph, when the stop light changed suddenly. I must have hit the brakes a little too hard, because the rear end did it's best to become the front end (e.g. nearly spun). The road was wet from the recent rains in the area, but I didn't expect this to happen. The car is a four-wheel power drum car. Should there be a proportioning valve in the system, or is that function handled by other means? Any suggestions on how to keep the rear wheels from locking up so quickly, other than not braking so hard?
I'm looking into buying a four-wheel disc setup, but that probably won't happen for several months. Is a proportioning valve required there as well? Sorry for the confusion, but surfing through Google provided more disagreeing opinions than any useful information. Thanks in advance for the help.
Improper adjustment of the brake shoes and mismatched wheel cylinders are the primary "gripe" of drum brake systems. A four wheel drum system can be safe and reliable, but all components need to be correctly selected, installed, and adjusted.
Misadjustment is the major reason people dislike drum systems. Maintenance and adjustment is easy, but it actually requires attention. Discs are self adjusting and easier.
All brake systems have front/rear proportioning valves. Having the correct valve and correct master cylinder are critical.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
Vikki is correct generally speaking. If drums are gone through and EVERYTHING new, wheel cylinders, spings, clips, shoes etc. on ALL four corners and then properly adjusted, 4-wheel drum is not as bad as most make it out to be.
However, with that being said, I have now owned the following and can offer first hand opinion. My 68 Camaro RS/SS conv. car had rear drum w/ front disc. Nice combo and all worked well and MUCH safer/reliable than my 68 Bird with all four drum with EVERYTHING replaced and all new. Even with new, properly adjusted 4-wheel drums our Bird was never safe when there was even just a bit of water on the ground. Each drum would lock up at different times etc. Very unsafe overall.
Then, when we bought our current vehicle, 67 LeMans, it too had 4-wheel drum. They were all original parts and VERY SCARY! Rather than spending the money to rebuild all 4 I opted for a 4-wheel disc brake system. As mentioned above front disc & rear drum are better than all drum, but 4-wheel disc is 10x better than front disc/rear drum.
So all in all each configuration is better than the next. Personally, now that I have owned all combos, I wouldn't even consider owning another classic car without 4-wheel disc. There is just NO comparrison at all from a safety/reliability standpoint IMO...
I was planning on upgrading to a disc setup eventually, but that scare yesterday has put it at the top of the priority list. It was still raining lightly, but the roads didn't have standing water on them. Looks my Bird will have to be a fair weather car for a few months.
Out of curiosity, what system/who did you guys go with? I've been looking at a setup from Matt's Classic Bowtie (pretty sure it's the same as Inline Tube), but the price is in the $1200 range.
I bought mine off Ebay from a company in CA called CPP (classic performance products). My power, 4-wheel disc conv. kit cost me $775. The ONLY thing it did not include was the pre-bent brake line kit, which I HIGHLY recommend! That was another $89.
All in all, their kit was excellent. They did fail to ship me the Pontiac only, axle spacer things. They overnighted them to me and all worked out well. I will say one thing though, this is a bigger job than some would lead you to beleive. My car was on a lift, had the help of a seasoned mechanic and it still took every bit of 3-4 days total...
