Nosediving Yukon

When Applying the brakes, particularly at low speed,(15mph or less) My 97 Yukon nose dives as if there were no rear brakes or the fronts were coming
on much sooner than they should. Adjusting the rears up to drag a bit seems to help a little but only for 3-4 days and it's right back to the nose-diving. Any advice welcome. Regards, JR
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Weak front suspension? Your vehicle is ten years old now...
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Are you sure that the rear brakes are actually being applied when you press on the pedal? I don't know if it's possible but maybe your rear master cylinder is not working properly.
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Nosediving Yukon Group: alt.autos.4x4.chevy-trucks Date: Sat, Oct 21, 2006, 9:25pm (EDT+4) From: snipped-for-privacy@freesail.net (JR) When Applying the brakes, particularly at low speed,(15mph or less) My 97 Yukon nose dives as if there were no rear brakes or the fronts were coming on much sooner than they should. Adjusting the rears up to drag a bit seems to help a little but only for 3-4 days and it's right back to the nose-diving. Any advice welcome. Regards, JR
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% "Sometimes, it is better to remain silent and be thought of as a fool than to open your mouth and remove all doubt." ~ Unknown ~
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Does this happen this first few stops of the day? My 2000 C2500 front brakes grab at first and then mellow out. A friend told me his Suburban does the same thing. Why? I haven't been able to determine. Steve
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It does it all the time. Particularly when turning into a parking space. Very embarrassing.

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Might be that both front hoses are decayed inside and have become check valves keeping some pressure on the front calipers, thus jumping ahead of the rears as the pedal is applied.
Similar thing happened on my 93 c1500 but only on one side. As I applied the brake pedal, the steering wheel turned as if they were mechanically connected. Letting off perfectly reversed it. Low chance both hoses could have the problem at the same time, but you never know. They've been under nearly exact operating conditions.

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Something very similar happened on the Caprice Classic I used to drive... Somewhere in the brake line was a clog that made this very thing happen. The mechanic replaced the caliper twice before he figured out what was going on... (he wasn't a great mechanic, and I was 16, so I didn't know any better). After a while the pad would wear down to nothing and then the whole brake system on that wheel would commit suicide.
But I agree, it's weird to think that it'd happen to BOTH wheels. Bad porportioning valve??? (just throwing out a guess, as I don't know about the brake setup on a '93...)
~jp
News Skimmer wrote:

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Sorry, I should have mentioned that I replaced both calipers and pads last month. I will ck alldata and see what they have to say about the proportioning valve. Could a faulty ABS sensor cause this?

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At the risk of becoming a Snojob,
I'd recommending just getting it over with and replace the hoses. They are cheap and easy....depending on how well your wife or girlfriend (not both though) can help you bleed them after.
The problem I had with the one hose on the 93 showed up the day I replaced the pads....I suspect the inner of the hose peeled back or something when I pushed the piston in.

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