Ford 9" with F150 drums, not holding enough

[postal]

I put a mosier 9" in my TTA. I went to the bone yard and got the drum brakes off an F150. I put new wheel cylinders and pads in them and when I tried to hold boost I only got around 5#'s. I then put a new master cylinder and have only got to hold 10 #'s like twice all the other times I can only get 8#'s. Any ideas on whats messing me up?

TIA: Jason

 

[postal]

any one?

 

[KEVINS]

You may want to get an adjustable proportioning valve so you can re-direct more fluid/pressure to the rear brakes..

 

[Jeff Rand]

I had a similar problem with my 11" rear brakes. I was using semi-metalic pads and switched to a softer shoe (usually the least expensive shoes are the ones to buy). Also I purchased two sets of the non-metalic shoes and combined the sets so that I only have the long shoes on each axle. It is a tight fit with respect to installing the drum, but it works great. I did a search on the web to get the shoes for this application (my shoes are for 11"GM drums).
Good Luck,
Jeff
PS I also installed the replacement brass proportioning valve and a Summit valve to restrict pressure to the front brakes. This was done to my powermaster setup prior to the above brake mods.

 

[postal]

I am running the 2 long pads on each side and they are the cheap pads(softer). Does any body make an adjustable proportioning valve with the correct meteric fittings?

TIA: Jason

 

[GNVAIR]

Just out of curiosity; Why did you replace your rear discs with drums? I know Moser has GM style flanges that accept the pressed style Ford bearing that would allow you to retain the rear discs. Again, just curious.

 

[postal]

Well I was told you had to go to drums to hold good boost. Also at this time I would not consider running a trans break. Maybe some day I'll go to a trans break and be a supporter of them. Right now though I dont see my self ever trying to use one. So it at least apeared to me that I had to go to either a t-break or drums. I used to only be able to hold 3 to 5#'s with the discs and that was with using the e-break too. I have been seeing guys saying they are holding much higher boost with there stock breaks than I was. Seams like I need to look into this proportioning valve deal. Maybe it isnt working properly and was holding me back on the stock breaks, and now.

A buddy of mine told me to put in a jumper valve that bypasses the proportioning valve. This will send full pressure to rear breaks and I'll be able to hold big boost. I may try this but it sounds like a cover up fix. I would prefer to try to get my breaks working right first.

Jason

 

[elcamino383]

hey postal... ever find a cure? im having the same problem with my 383 el camino... cant hold much throddle on the line... i have baer 12" discs....

 

[postal]

I went to wheel cylinders that where around 30% bigger and still no real luck. I think I'm going to have to try a new proportioning valve. I dont think this is a 9" only problem because the amount of boost people can hold even with the stock rear ends varies greatly.

Sorry I cant be of more help, but if you find a solution that helps you PLEASE let me know.

Thanks: Jason