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Author Topic: cj7 rear brakes locking easily  (Read 6969 times)

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BIGDRY

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cj7 rear brakes locking easily
« on: August 03, 2016, 11:16:52 AM »

Hello all, well ive finally got my cj7 back on the road , got a few issues....

first major one to address is the rear drum brakes lock on easily when braking reasonably hard, ive had both drums off and the biggest issue i could see is the brake self adjuster cable is stretched and not providing  much tension on the self adjustor - especially on the off side which tends to lock the easiest.... the adjuster lever hardly touches the star wheel at all...
 
Does anyone know somewhere in the uk that i can buy just the adjuster cables  - i see rock auto do such a kit , but id like to get them quickly..

Also any tips in setting up rear brakes so they dont lock easily? :)

thx
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General Confusion

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Re: cj7 rear brakes locking easily
« Reply #1 on: August 03, 2016, 11:51:06 AM »

I may be asking the obvious, but are the shoes the right way round and paired correctly?
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wildwood

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Re: cj7 rear brakes locking easily
« Reply #2 on: August 03, 2016, 02:52:06 PM »

Lighthouse do kits of all springs and cables for the rear drums.
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Delk

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Re: cj7 rear brakes locking easily
« Reply #3 on: August 03, 2016, 03:22:30 PM »

If the rears are locking up this doesn't sound like an adjustment issue to me. I would be looking at the proportioning valve or something else.

The adjuster could still need some work but it doesn't sound like the cause of the problem.
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wildwood

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Re: cj7 rear brakes locking easily
« Reply #4 on: August 03, 2016, 04:13:52 PM »

 :iagree:
the adjusters only work when you put handbrake on. And that's when the lever hits the star wheel and gives it a click more. You could run without them..... Just have to get under more to adjust the brakes :icon_twisted:
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Dave The Sparky

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Re: cj7 rear brakes locking easily
« Reply #5 on: August 03, 2016, 05:13:36 PM »

:iagree:
the adjusters only work when you put handbrake on. And that's when the lever hits the star wheel and gives it a click more. You could run without them..... Just have to get under more to adjust the brakes :icon_twisted:

Not true on CJs wilwood the adjuster is designed to move the lever when reversing and applying the brakes.

Are your front brakes working okay? Does it seem the rears are doing all the work?
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Dave69

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Re: cj7 rear brakes locking easily
« Reply #6 on: August 03, 2016, 06:21:33 PM »

i adjust the rears on mine when i find its not stopping quickly enough. great round town in the wet going down a hill, certainly attracts attention the sound of a locked wheel and the tyre screaming in protest
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wildwood

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Re: cj7 rear brakes locking easily
« Reply #7 on: August 03, 2016, 08:55:10 PM »

:iagree:
the adjusters only work when you put handbrake on. And that's when the lever hits the star wheel and gives it a click more. You could run without them..... Just have to get under more to adjust the brakes :icon_twisted:

Not true on CJs wilwood the adjuster is designed to move the lever when reversing and applying the brakes.

Well waddyaknow. I was going to say that and then I thought......I bet I'm wrong......but what a thing I now know I would have been right... Trouble is when I had that system on the YJ I always ended up taking the drums off and. Hosing them out before readjusting the brakes manually. I am sure it's a system that only works marginally when you stick to dry roads.... :icon_twisted:

Are your front brakes working okay? Does it seem the rears are doing all the work?
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5536paulj

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Re: cj7 rear brakes locking easily
« Reply #8 on: August 03, 2016, 09:09:13 PM »

Sounds like a stuck proportioning valve to me, have you tried pushing the little pin in and out. It's on the pass side chassis rail just behind the engine
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BIGDRY

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Re: cj7 rear brakes locking easily
« Reply #9 on: August 04, 2016, 12:27:55 PM »

Thanks all for the helpful comments.

I need to check the shoes for sure - when i last checked them i didn't know there was a difference, its possible they are incorrect by PO. but he slack in the adjuster cable isnt a good sign admittedly but i thought that if anything would mean that the shoes wouldn't adjust up as they wear

I seem to get most locking on the offside rear only so i didn't think it was proportioning valve - but as i sit on the left hand side (lhd) i guess it is the most unloaded. Also it could just be that this one brake is more susceptible than the other side. im surprised the rear drums can lock up wheels so easily but i guess the rear of a cj is pretty light.

Does any one know if the proportioning valve is the type that provides less rear bias under braking or is it a fixed bias?  thx all again.
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Delk

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Re: cj7 rear brakes locking easily
« Reply #10 on: August 04, 2016, 02:18:59 PM »

Under heavy breaking the proportioning valve should limit pressure to the rear brakes. The front brakes should always lock up first otherwise you will end up facing the wrong way as the back passes the front.
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Mike Pavelin

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Re: cj7 rear brakes locking easily
« Reply #11 on: September 10, 2016, 05:33:23 PM »

I may be asking the obvious, but are the shoes the right way round and paired correctly?

 :icon_super: Took them apart today and..... the (ahem) person who fitted the brake shoes had fitted both leading shoes on the right hand side and both trailing shoes on the left. :banghead:
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Dave69

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Re: cj7 rear brakes locking easily
« Reply #12 on: September 12, 2016, 11:39:44 AM »

well at least the problem js now solved
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Re: cj7 rear brakes locking easily
« Reply #13 on: September 12, 2016, 02:23:45 PM »

Well done, Sir.
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BIGDRY

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Re: cj7 rear brakes locking easily
« Reply #14 on: August 07, 2017, 04:11:27 PM »

Hi All, prob not solved..:( Despite re adjusting a few times now the rear brakes still end up being too aggressive on the rear once they have self adjusted up fully.

i have noticed that the combination;/proportioning valve has it little pin stuck in - i think this is sending too much fluid to the rear all the time.

Anyone else had this? you adjust up the rear brakes and at first its ok , but gradually they settle in and adjust up fully after a few miles then rear brakes are too active.

was thinking  of ordering this part? as rock auto/crown etc  dont seem to offer this a replacement?...

http://www.ebay.co.uk/itm/1974-86-74-86-JEEP-CJ5-CJ7-PROP-COMBINATION-PROPORTIONING-VALVE-PV2-DISC-DRUM-/262592807096?hash=item3d23c040b8:g:1bYAAOSwhOVXdMFu

cheers
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Re: cj7 rear brakes locking easily
« Reply #15 on: August 07, 2017, 06:24:02 PM »

If you can hold of Dave the sparky he put a manual proportion valve on his and adjusted it what he wanted.

Don't think it was too expensive.
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5536paulj

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Re: cj7 rear brakes locking easily
« Reply #16 on: August 07, 2017, 07:26:14 PM »

If i remember correctly the pin should be sticking out in normal operation, it may just be gummed up, but maybe just buy a new one at that price....
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Dave The Sparky

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Re: cj7 rear brakes locking easily
« Reply #17 on: August 07, 2017, 07:53:23 PM »

I used one of these on the 8 as i have 11" drums and not the standard 10" but i was also fitting all new brake lines so it may not be a straight swap for you if you bought one as i seem to recall the pipes to the rear brakes are a bigger diameter than the front ones and may have bigger fittings.

Prop Valve Hyperlink thingy!

It does work very well and great fun can be had whilst fine tuning it in your nearest flat area/car park so the fronts lock first!

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Dave69

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Re: cj7 rear brakes locking easily
« Reply #18 on: August 08, 2017, 04:54:10 PM »

Just dont set the bias when its wet
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BIGDRY

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Re: cj7 rear brakes locking easily
« Reply #19 on: August 18, 2017, 09:25:15 AM »

ok rear combination valve ordered. lets see if that helps.

The pipes to the original valve look past their best however.

Does anyone know what flange type and union tyres are fitted to cj7 originally?
I might order flaring tool and unions in advance...
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Dave69

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Re: cj7 rear brakes locking easily
« Reply #20 on: August 19, 2017, 12:26:36 PM »

old imperial ones where you cant get them easily here.

or talk to light house
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Dave The Sparky

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Re: cj7 rear brakes locking easily
« Reply #21 on: August 19, 2017, 02:21:02 PM »

Most of them are 3/8 UNF but as i said before i have a funny feeling the rear brake line is bigger.
You need the long threaded ones, standard ones are too short and ignore old 69er they are easily obtained from Ebay. or these guys in lovely non corrosive brass too! :icon_winkle:

https://www.automec.co.uk/products/brass-brake-pipe-fitting-male-3-8-x-24-unf-3-16
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BIGDRY

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Re: cj7 rear brakes locking easily
« Reply #22 on: August 22, 2017, 11:35:54 AM »

Cheers Dave
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BIGDRY

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Re: cj7 rear brakes locking easily
« Reply #23 on: October 12, 2017, 10:57:41 AM »

hi all, the aga continues!

Finally got around to try and fit this new brake combination valve that got sent over from the states.
Getting all the old pipes off was great fun, but I managed it without breaking anything!

However the new combination valve supplied has a 9/16 18 tpi 1/4 pipe size female fitting on it where as the car has 7/16 18tpi 3/16 pipe an male fitting... 

Does anyone know any where in the uk that sells proper inverted flare, imperial, brake pipe adapters so I can some how reduce correctly down.
Im not 100% sure but i think i will need 2 fittings one to go from 9/16 to 7/16 then another to reduce internal bore down 1/4 to 3/6


I've tried all the local usual suspect such as Pirtek etc but all they do is bring out metric stuff.....  thanks
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Jonny Jeep

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Re: cj7 rear brakes locking easily
« Reply #24 on: October 13, 2017, 09:38:25 AM »

I'll have a look what imperial brake fittings we have in work later.
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