99 Yukon brake pedal becomes hard to press when braking suddenly. Power assist prob?

[99Vortec]

<SARCASM>I had the most wonderful hangover going when I replaced that little switch on my Yukon</SARCASM>




Seriously though, I also disabled my airbags before starting. And the little clip that holds the switch on is a bit tricky to remove.

I got mine off without damaging it. Looks like you are missing the retaining clip completely. Does the new gm switch come with the clip?

 

[SunlitComet]

no but dorman "help" products have a variety pack for a few dollars that includes the one you need to replace it.

 

[MarkD51]

ha, good luck with that.

I take it that it is difficult SLC? Why, is there a long, or buried wiring harness-connector to get to? Or?

Sorry to hear the Brake Switch got broken. I didn't foresee this happening.

If I remember, I found a couple youtube vids of the booster install, and perhaps could've linked to them before you undertook this project, sorry that I didn't. In actuality, the removal, and re-installation of the switch itself once the clip is off is not at all hard, once one sees and understands how it attaches.
Mark

 

[SunlitComet]

the brake system structure mount is is the way. normally mot that bad except the steering column is just below it and that is what really makes it a pain. btw my column was removed so i could do my hydro install so doing the switch was easier since the whole assembly was being yanked out.

 

[MrSpicy]

OK guys so I replaced the brake switch fairly easily. Also the new clip went on easy enough. The AC Delco switch I ordered did not come with the switch but as SLC said the doorman kit works well comes with both the newer and older style switch clips as well a plastic one.

Mark I did find a few good YouTube videos for the booster. I think the switch may have just gotten damaged wile taking it off. Also figure its spent 15 yrs being used.

But this was not where the fun began. No mater what I do, we cannot seem to get the brakes bleed properly. My dad and I spent way to many hours trying to get the damn things bled but no matter what the pedal feels like shit and goes down about 3/4 to brake. I know these things have ****** brakes but its never been this bad.

Finally gave in and have been driving it, I couldn't stand driving our Camry to work any more and it sure has been nice to have my Yukon back. Lets just hope no one pulls out in front of me too quick.

Just wondering if anyone has any idea what might be the problem. I had bought one of those vacuum bleeders but it didn't work so it was done the old fashion way. Only thing I can think of is I don't think I've ever bleed a car with abs could this have anything to do with it?

 

[SunlitComet]

if the switch did not come with the switch then how did you get the switch?
actually they have good brakes when operating properly. rears adjusted correctly? the abs bleeding is more complex and to put it simply if you get bad pedal results while parked the abs should not be the issue as the isolator valves in it should let the fluid run freely thru it.

 

[MrSpicy]

switch clip was not included***

Pretty sure the rears are good, adjusted them till where they barely catch the drum when I put them on- unless there is something I am missing.

I suppose the brakes never worked as good after I did the pads and shoes but I assumed that had something to do with having to bleed them since I had to replace both rear wheel cylinders which required bleeding. And it didn't go so well that time either but we got it to pretty much normal.

But now since replacing the MC and booster I cant get them to feel right. They are usable but not ideal. Need to get them good enough so the wife can use it if she needs to.

One thing I forgot to mention when bleeding the pedal would only go down about half way with the rear and fully to the floor with the front. Its been a long time since I was the one doing pedal pressing but I dont recall that being normal. Any thoughts?

 

[SunlitComet]

i dont recall that being normal either. i was not on the pedal end last i did mine earlier this year. hopefully someone here was. it may just be the proportion valve trying to isolate what it thinks as a link i would guess. i don't get to do. the last time i did mine before this year was 4 years ago. i use a specific set of parts to achieve my braking needs so even with my hard braking they hold up stronger and longer. i would think that unless the booster is boosting there should not be enough force on the mc to trip up the valving. could be the mc internal follow up valve doing its thing under bleeding. i just can't recall what it did last time i was on pedal duty. for the rears are you adjusting, putting drum on, hold down with 2 nut and checking fiction response and if needed redo it over again? have you thought about a pressure bleed at a shop?

 

[MrSpicy]

for the rears are you adjusting, putting drum on, hold down with 2 nut and checking fiction response and if needed redo it over again? have you thought about a pressure bleed at a shop?

Not sure what you mean exactly by the 2 nut. I just adjusted until it slightly grabbed the drum and that was that.

As far as taking it to a shop it looks like that's what I may have to do. I just hate the idea of ass hats working on any of my vehicles. Also wanted to rule something else before i waste the money on a shop only to have it not fixed. But that's probably what I will do next.

 

[SunlitComet]

drum held on with two opposing lug nuts to ensure it is seated properly.