90tbi305

In about two or three weeks i am going to swap my 10 bolt open for a 9 bolt posi disc rear.

I was woundering what will happen if i dont change the proportioning valve and just leave the stock drum valve.

Yesturday i went to a place that they only sell f-body parts, and asked for a proportioning valve for the swap i want to do and they told me that i would need to get a 82-84 proportioning valve that came of a car with disc. Becouse the threads on the newer cars were different.

Can anyone give me some advice, or help me with this little problem i have. -Eric

savage_racing

If you don't change the valve, the rear brakes either come in too hard or too soft, I don't recall which but, it don't work proper.

for the aggrivation of having to bleed brakes, might as well do it right the first time, you know what I mean.

five7kid

iTrader: (14)

You need to avoid the pre-'84 valves because they have SAE fittings. You need metric fittings.

MrDude_1

wrong.

it works fine.

its not ideal, but it does work good and is far better then stock.

if you do decide to change them, you need a 85-92 4 wheel disc valve.. the earlier ones have a diffrent thread then your 90.

90tbi305

So you are telling me that if i stay with the stock proportioning valve it will work?

Any ways the drums really dont do too much work.

-Eric

MrDude_1

yes they work.
yes they stop better then the stock drums.

however, they wont stop as fast as they potentially could with a diffrent prop valve. how much of a diff vs the stock Disc/Disc valve? not much. how much vs a aftermarket adjustible... more then enough to justify the cost and time of installation.. in my opinion.

what i would do (or i should say, what i did do) is drive with the stock disc/drum prop valve, and on your next full brake service, put in a new aftermarket wilwood valve. also when you do that, its a good time to put in new flex lines, stainless or factory replacement, doesnt matter.

novass

iTrader: (1)

I got a new prop valve for my 90 formula for my LS1 front/rear disk swap. The GM PART # 10164112 Late 89 to 92 valve 1.5M .

cost me about $65 shipped New.

savage_racing

Now hang on, I'm not here to **** and moan but how can you tell me I'm wrong. the only thing you've done is said that yes it comes in a little harder/better. All you have done is eliminate where I was confused.

Don't say I'm blatently wrong when you are clarifing my comment. That's just plain rude and ignorant.

MrDude_1

that statement is wrong.

they work properly. fine. correctly. safely. however you want to phrase it.

so, i said:

wrong. it works fine.


doesnt seem rude or arrogent to me. it works properly


i apologize if it came off as rude, i was just correcting that last statement.