Brake shudder when stopping from 40 mph or more,'99 f-150

I’ having trouble with the rear drum brakes on my truck, could the drums be out of round? the shudder only happens when i apply the brakes at 40 mph or more. also the left rear wheel locks up very easily at low speed , 5 mph or less, when i first start down my driveway. i did an inspection yesterday and the shoes and drums are in very good shape, i did this brake jobabout 5 months ago to try to solve a similar problem, and here i am again. also installed new rotors calipers and pads on front this week, they seem to be fine.

Rear drum brakes can be tricky to install…The emergency brake linkage is critical, the self-adjusters, and the fact there is a leading and trailing shoe all can cause serious problems if the brakes are not correctly assembled and installed…Did you have the drums turned when you replaced the shoes??

well i installed new drums on both sides, i was having trouble with the parking brake not disengaging. … the truck is manual tranny… so replaced main e brake cable and cable to left wheel. i was thinking about disconnecting e brake to see if that has any effect. thanks for reply! one thing i didnt do was apply high temp brake grease to the shoe backing plate, when inspected yesterday both drums removed without locking onto the shoes, left was a little tighter though.

Today, most replacement drums and rotors are made in China and one can not assume they have been perfectly machined or have not been mis-handled in some way. it might be worth taking them to a machine shop and having them cleaned up or at least checked. That’s the only way to be sure…

Usually, with drum brakes, one shoe will have more lining material on it than the other. Those larger shoes go towards THE REAR of the vehicle. The smaller (leading) shoe goes toward the front.

thanks again caddyman, i will check that the shoes are inthe right place and recheck everything, yes these are china drums.

had the drums turned and bought new shoes, the brakes work excellent now. no lockup, no shudder, wow! i used a different brand of shoe, only 20 usd for both sides, and asked the tech that turned the drums how they were, one was a little out of round the other was near perfrct. i didnt detect any major flaws in the way that i put these brakes back together lasttime, but i did closely follow the haynes manual this time, and it really helped as far as the order in which to put the brake parts back in place. about the shoes ,in this application the shoes, front and back are the same size both the lining material and the actual metal shoe/bracket itself, what is different is the location of the lining material,shifted about an inch an a half on the fron versus back shoe and … the thickness of the lining material, front versus back shoe, interesting! i wonder if these previous shoes that i installed were like this.
Thanx all, Ken

They should have been. Usually the primary shoe lining is shorter to help the shoes servo (Front one help the back one jam harder against the drum). This also helps the adjusters work on older models. Some newer ones adjust in different ways. The primary shoe lining is usually thicker too.