I just converted from manual drums to manual disc using SSBC Kit. I don't feel a difference.
The peddle feels spongy. Is that normal or should it feel hard?
The shop that did the conversion left the distibution block in and didn't install the supplied prop valve. They said the braking was balanced as determined with all four wheels locking at the same time. I spoke to SSBC and they said that it is possible not to use the prop valve. What do you guys think?

Spongy pedal, probably have air in the system. Rebleed the entire system. Have them put the P valve in, you may want to or need to adjust it in the future.

Bob

Should there be a big difference in stopping?

Should there be a big difference in stopping?

Was that a serious question or are you goofing?

I have 4 wheel drum manual on my 68 camaro and 4 wheel disk manual on my 67 corvette. Honestly, I don't notice a difference.

Oops...neither are spongey. I agree you may have some air in there.

when i first got the Nova on the road after converting from power drums to manual 12" C4 Corvette discs in the front, i was a bit disappointed. yeah, it stopped alright- but so did the drums when they were adjusted right.
but i bled the brakes a few times, and actually bedded in the rotors and pads- and all of a sudden, it felt like i hit a brick wall when i slammed on the brakes. and they never faded or went out of adjustment after a few stops like the drums did.
i was pleased..

Once you get a firm pedal, try changing pads if you want more responsiveness. I felt a significant improvement going from Performance Friction to Hawk HP plus'.

I converted to front discs and my pedal was spongy with poor braking until I bled the ^*&%* out of them. After that you have to be careful so you don't touch the pedal too hard. Not kidding.

I just converted from manual drums to manual disc using SSBC Kit. I don't feel a difference.
The peddle feels spongy. Is that normal or should it feel hard?
The shop that did the conversion left the distibution block in and didn't install the supplied prop valve. They said the braking was balanced as determined with all four wheels locking at the same time. I spoke to SSBC and they said that it is possible not to use the prop valve. What do you guys think?

If the front and rear lock at the same time I could see why you feel there is no difference over the drums. The front should handle a greater percentage of the stopping and should lock before the rears. A spongy pedel is not acceptable, either air in the lines or bad brake hoses... The pedel shouldn't feel hard either, manual brakes will require more leg power but you should be use to that already. The disc's may require more leg than the drums and that may be why you don't notice any better stopping power.

Since you had a shop do this work, take it back to them and report the spongy feel. Also insist you want the prop valve installed and expected it to be as it was part of the kit. You'll have more leverage if you got the kit through the shop that did the work. If you provided the kit, expect to hear that they followed the directions and if it doesn't work to your liking it's not their issue... I should have asked if you paid by the hour or by the job? If you paid by the hour expect to pay more to get the job finished...

I will definitely get the prop valve installed just for piece of mind, it can't hurt.
As well as getting them to re-bleed the system.
If I don't keep the pedal to the floor all the way with a lot of force the car will inch forward, this coupled with the pedal feeling spongy leads to the conclusion that it needs bleeding. As for not being able to tell the difference, it is no Joke. There would be a differnce, I am sure, if I were to heat up the brakes, but at the first few times when the drums were cold absolutely no difference.!

Do we really want the front brakes to lock up before the rear?

Do we really want the front brakes to lock up before the rear?

Yes! If the rears lock first the car will skid and fishtail on you. The idea is to initially have the rear brakes activate first but the faster you stop the more weight is transfered to the front of the car so you don't want the lighter back end locking until the fronts do.

I might bet that if you call SSB that will tell you the prop valve is vital of the pressure distribution will be wrong. And yes, $5 says you have air.

I cannot fathom there being no difference. When I changed my T/A from rear drums to rear disc, the difference was night & day. Especially after repeated high speed stops. The drums would fade huge.

Bonzo, I love the name, for the obvious reason.(greatest drummer in my opinion)
I called SSB and actually they said that it doesn't neccessarily have to be installed. Depending on the wheels you were using, like if you had skinnys on the front and slicks on the back that would be a case that you would need to. But a car that had similar size tires front and back it Might not be necessary. They also said that the master they provide with the manual kit is for four wheel discs and because I had drums in the back I wouldn't need to install it. Whatever that means.

Ok, based on that last post, this is why I feel some tech support people just don't know what they are talking about!!

If they are saying that because you are running rear drums you do NOT need the prop valve, then they are feeding you a bunch of BS about either the drums or the MC they provide. Drums brakes require much LESS pressure to stop than disks, so if you have rear drums, then you SHOULD need the prop valve in the rear to keep them from locking! That is if the MC is putting out enough pressure to properly operate the rear disks! There is simply no way for an MC to functionally be able to both effectively!

Drums need only about 150 to 200 psi at the cylinders to be able to lock the wheels... depending on the disk setup, you will need anywhere from 900 to 1,500 psi... so to think the same MC can do both without some kind of a valve is ridiculous!

Bottom line IMO, if the pedal feels spongy, then there is still air in the lines or in the MC. If you get a firm pedal and then feel it doesn't stop as well, there may be other problems as well. If you get a firm pedal and don't install the prop valve, then $10 says you will lock up the rear drums pretty easily and that's not good!! Assuming of course that you really do have a disk/disk MC!! One of the big issues I see in some of these 'kits' is that they try and give you a 'universal' MC... but one size does NOT fit all in this case!!

Let us know how it goes and if you like it after re-bleeding the brakes.

Best of luck,
Bill C.

It sounds like they didn't bech bleed the master cylinder. I can't see why SSBC would tell you not to install their own part supplied with the kit. A drum drum set up requires a different valve than a disc drum as you have to hold off pressure to the rear to prevent lock up. Also poor brake performance can be due to improper pad break in and improperly cleaned rotors before installation. Easy solution take back and either demand refund or proper repair. Yes, you should feel difference unless you were running some HP type shoe set up such as Praise stuff. You have air and wrong valve. Bench bleed master off of car than prrssure bleed system. Good luck

The car is back at the shop tonight and will be worked on in the morning. One question, When you install the Prop valve do you remove the ditribution block?

About 6 years ago I did about the same upgrade as you: 68 4-way drums, added power front disc kit from Vette Brakes (made by SSB, I think). I had a highly regarded local Meineke shop do the install. He did put in the p-valve and kept the distribution block. Needless to say the difference was amazing, and the only problem I have is when my engine hasn't built up enough vacuum for repeated use of the brakes.

Got my car back today, I must say that I am not impressed with the Stainless Steel brake kit. I thought I would get improoved braking but I feel now with properly adjsuted drums you get as good stopping with the exception if they heat up. I also eliminated the shift to whatever direction when I applied the brakes which is a positive. It also turns out the back drums were out of adjustment. The prop valve did not get installed and after speaking with the SSB tech rep he confirmed that the prop valve would only reduce brake pressure to the rear and not increase pressure to the front discs. Also a point to note, they specifically said that you should never remove the distribution block when doing this conversion. I am not sure where I am going from here on the brakes but this set up will be out of there. Thanks for all your help :waving: