14BFF Brakes Locking Up - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71K20chevy · 03-14-2015, 07:54 PM

Recently we swapped a 14 bolt out of a 79 K20 into my 71 K20, replacing the original Eaton HO52 that blew up. The HO52 had 1/4" brake line while this one has 3/16". The proportioning valve and everything is unchanged. The wheel cylinders were also leaking pretty badly, we replaced those, the shoes, and the hardware. But they still lock up if you brake hard! Do the shoes need time to break in? I was wondering if the smaller 3/16" line is causing too much pressure to be sent to the rear, since the proportioning valve is set for all 1/4" line. Also, the brake light is not on. I get my license in a couple days and definitely want everything working correctly so I don't wreck it.

Thanks!

71K20chevy · 03-20-2015, 01:24 PM

Ttt

k_n_browning · 03-20-2015, 08:09 PM

Ok you need to measure the brakes on the 14 bolt then the ho52.also do the wheel cylinders.If the ho52 is larger then this will be the problem.The brake line needs to be the same size.Bottom line it has to be all the same size.If not you will need a porp valve if its close.

03-14-2015, 07:54 PM	#1
71K20chevy Registered User Join Date: Jul 2012 Location: Ft Wayne Indiana Posts: 1,205	14BFF Brakes Locking Up Recently we swapped a 14 bolt out of a 79 K20 into my 71 K20, replacing the original Eaton HO52 that blew up. The HO52 had 1/4" brake line while this one has 3/16". The proportioning valve and everything is unchanged. The wheel cylinders were also leaking pretty badly, we replaced those, the shoes, and the hardware. But they still lock up if you brake hard! Do the shoes need time to break in? I was wondering if the smaller 3/16" line is causing too much pressure to be sent to the rear, since the proportioning valve is set for all 1/4" line. Also, the brake light is not on. I get my license in a couple days and definitely want everything working correctly so I don't wreck it. Thanks! __________________ 71 K20 64 GMC mud truck

03-20-2015, 01:24 PM	#2
71K20chevy Registered User Join Date: Jul 2012 Location: Ft Wayne Indiana Posts: 1,205	Re: 14BFF Brakes Locking Up Ttt __________________ 71 K20 64 GMC mud truck

03-20-2015, 08:09 PM	#3
k_n_browning Registered User Join Date: Sep 2011 Location: McAlester Olahoma Posts: 114	Re: 14BFF Brakes Locking Up Ok you need to measure the brakes on the 14 bolt then the ho52.also do the wheel cylinders.If the ho52 is larger then this will be the problem.The brake line needs to be the same size.Bottom line it has to be all the same size.If not you will need a porp valve if its close.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.