i'm in the final process of switching from rear 4 lug drums to 5 lug rotor, and 4 to 5 lug front rotors, going with coilover suspension

just waiting for parts to come back from powdercoat, to get everything installed

my question...is the proportioning valves going to be an issue, something i had not given any thought till someone at work brought it up in a conversation

i am talking about my 2005 LS

 

no opinion ?

 

bump

 

Yes its going to be an issue if you dont have ABS. This has been discussed at length before many times, I was the very first to switch to 5lug, and to 4wheel disc on a non SS car. I I put drums back on the rear because the bias is way off and i didnt feel like installing 2 aftermarket proportioning valves. (I currently have LSJ fronts and drum rear, works awesome.) There is a work around for it, it involves parts from other GM vehicles including modified parts. If you are creative and figure out the combo it will work correct, I decided it wasnt worth the cost to replace all the parts I already had. And the difference in price for all the new parts and the effort to modify parts wasnt worth the marginal increase in ease of brake modulation available from the rear discs.

 

i have way too much invested to back out now

most parts have been powder coated, instalation in a couple of weeks

and no my cobalt is not equiped with ABS

what would be the best soulution, is there no way to program the computor (tune)

 

If you dont have ABS there is no computer involved in the brakes.........

If youve got all this money invested and you didnt think about brake functionality until now then thats a big problem, and sometimes poor planning costs you money. Hard lesson to learn.

If you choose to continue to go forward with this and use the rear discs youre going to need to get two aftermarket brake proportioning valves, and install one into each hydraulic circuit for the rear wheels, its then going to take alot of tweaking and adjusting to get it dialed in right. This will require some time and hopefully some wide open spaces or a racetrack where you can safely test the limits of the brakes while you adjust.

Doing it without adjustable valves and testing the way I suggested is just goin to put you and your car at risk in the future.