Weird brake issue... can't figure it out!

[Nefarious]

I'm having a strange brake issue on my 92 pathy. The brakes feel fine under normal light use, no noise or vibrations, but as soon as I need to brake moderately to heavily, the vehicle shakes quite violently. It feels like the noise and vibration is coming from under where my feet are under the floor.

 

It's not a typical ball joint clunk, it's a repetitive ratcheting noise and vibration that does not feel too good. It's kind of like abs is triggering but I feel it in the front, not the back, and it's happening far too soon. I am by no means emergency braking when this happens, but I do notice that one of the tires seems to screech lightly on the left side when I brake with any force(happens a bit before the noise/banging in relation to brake pedal force). The brakes smell hot on the rear of the vehicle after a drive so I'm guessing my rear calipers are fairly seized. I ordered new rear calipers that will be here tomorrow.

 

basically, my question is; would a seized rear caliper(s) cause abs to engage far too easily than it should, and also, is it normal to feel the vibration from abs under the front/middle of the truck when it engages, or should I be looking somewhere else for the issue?

 

The truck has a trailmaster 4" suspension lift so it has some extra bits underneath if that makes any difference.

Edited February 15, 2015 by Nefarious

[Kingman]

A stuck caliper can warp the bejesus out of a rotor in a hurry. Some brake shakes don't appear until you're traveling faster, or when the rotors get hot. Other times only light braking makes the shake come out. Literally some people have no idea it's even there as they just putt around town and don't travel fast. It's when I run them down the highway and come to a stop that the vehicle shakes to high heaven.

 

Might not be the caliper its self either, could be the slides seized up. Always lube the slides and contact points with a good brake lube every time you service the brakes.

 

Does it shake the steering wheel side to side or do you feel it more in your butt? There's

 

I've never had ABS shake the vehicle like a brake shake. Just the noise/feel in the pedal and some lurching from the tires locking/unlocking quickly. Although an ABS stop on something with bad calipers (uneven braking power) can be pretty unnerving as it can jet the entire vehicle left to right. However it's not easy to generate a full on ABS stop on dry pavement and it does not feel the same as a warped rotor.

 

there are times that a warped rotor gone intended to rattles the caliper bolts loose. That's noisy, scary, and downright dangerous.

[ahardb0dy]

probably a warped rotor

[adamzan]

I would second the suggestion of warped rotors. Also make sure nothing is loose. Like the uca to frame bolts.

 

The rotors on my brothers golf pulse only under braking from high speeds. Around town you never noticed.

Edited February 16, 2015 by adamzan

[Nefarious]

That's the thing. It doesn't matter if it's high or low speed. I can be doing 20 kmh or 120 kmh and it's the same. It actually happens a bit less at higher speeds. It's based only on brake pedal pressure. I'll get my rotors surfaced and put some new pads on along with the new rear calipers, hopefully that does it ! I did find that my tension rod bracket extension had a few bolts that worked loose a bit on the trailmaster lift so I re torqued it all. Haven't had a chance to test it yet. I'll get new pads and resurface the rotors as well as replace the rear calipers. That better do it ! Lol

[adamzan]

You could always take the tires off and see if there is an imprint on the rotor that is kind of in the shape of the brake pad. I have seen this a lot and its from people who slam on the brakes at the last moment and hold them there at a red light.

[Nefarious]

Okay. So i replaced the rear calipers and pads, truck brakes great now. No pulling, no hot rotors.

 

So I've ruled out warped rotors, there is no vibration at all under normal braking and even a quick stop from 120 kmh down the highway proved perfect, there is also no vibration in the steering wheel. When I can get it to clunk I only feel it under my butt and feet. Steering wheel feels fine. Everything feels normal, no vibrations at all.

 

The only time I can get the noise/clunk clunk clunk to happen is if I brake hard at SLOW speeds. Like 20-50 kmh is the only time it will happen at all. Drove 45 km each way to work today and it drove beautifully. I torqued all the bolts under the truck including control arms and all the trailmaster lift bits.

 

Today after work I crawled under and noticed something though. My rear drive shaft has wear rings around it where it's rubbing my crossmember. I think when I slam on my brakes at low speed, it's enough to shift the vehicles weight enough that it lifts the rear end up and rubs the drive shaft. The only part I don't understand is why I hear a loud repetitive clunk sound and not a continuous scraping noise, maybe it's sort of skipping, rather than continuously rubbing? This weekend I am going to notch my crossmember and patch in some new steel to make a U shaped center section which will allow the drive shaft room to flex. HOPEFULLY this fixes it. I am running out of ideas of where to look lol. 7" of suspension lift is definitely pushing it without some reworking of the frame I suppose, lol.

 

I have some ball joints and wheel bearings in the mail as well, so I'll have the entire front end rebuilt once these last parts show up and that will eliminate that bit.

 

 

one other thing I notice a slight ticking sound that I'd also repetitive in my front left wheel area when applying brakes very lightly. It almost sounds hub related as its like an actual tick tick tick sound like the hub is trying to catch and then failing or something. So a front hub/joint rebuild is in the works next...

Edited February 18, 2015 by Nefarious

[kdj]

I will quote you "quick stop from 120 KPH". Glad you don't drive on my road..

[Nefarious]

As in a normal accelerated stop on the highway at a stop light. The speed limits here are 120 kmh lol.

[kdj]

Sorry I didn't know they had those limits in BC, I haven't lived there in 20 years. It's 80KM in Ontario and I've had 2 dogs and a sister killed by speeders, so I'm not a big fan of it.

[Nefarious]

Ah that's understandable. Keep in mind I live on an island with quite a low population. The stretch of highway I commute on is 120 kmh limit because it's a long stretch and very little traffic. In my 40 minute commute to work, sometime I will not see another car from either direction for 5-10 minutes at a time. Depending on the time of day, you could commute from one town to the next without ever seeing another vehicle. It is quite barren and empty! I would not be testing my brakes if there was other traffic around, and I most definitely was not speeding.

[adamzan]

Ontario has the worst speed limits in the country. It's 80 in most places where 90 or even 100 is perfectly safe. All highways are 100 but you will never get a ticket unless you are going over 120 (not that I do since the truck is too thirsty at that speed). They should just raise the limit and be more strict with enforcement like they are in the US. The limit going down to Florida from here is usually 65-75 but if you stray even a couple mph over that they will nab you.

 

Here you get those retards that will stay in the far left lane going 90 in a 100kph zone and purposely slow you down since they think they should control what speed you drive at.

 

I think 7" of lift is pushing it for the stock suspension geometry. You might want to look into the adjustable trailing arms.

Edited February 18, 2015 by adamzan

[Nefarious]

I am most definitely looking into adjustable arms as well as shifting my spring perches so that i run a proper pinion angle. I have finally found a perfect wd21 with no rust that I can build my dream path out of! Actually stopped in at a frame coat shop today to see what it would take to preserve my frame indefinitely and I might have found what I need, lol. Want this to be one of those rigs I can pass down to the next generation!

 

Also looking into converting the front end to coilovers and removing the torsion bars, then I can do a medium travel setup since my diff can be moved pretty easilly by modifying the lift brackets. Have a buddy that is a red seal welder so if I can come up with it, he can do it for me (I don't trust my welds yet for suspension work)

 

and I agree about the speed limits in quiet rural/town areas. We have an incredibly low accident rate and the insurance rate is very inexpensive to suit. It's a very large area with a small population per capita, hens much room to move around.

Edited February 19, 2015 by Nefarious

[SpecialWarr]

Ontario has the worst speed limits in the country. It's 80 in most places where 90 or even 100 is perfectly safe. All highways are 100 but you will never get a ticket unless you are going over 120 (not that I do since the truck is too thirsty at that speed). They should just raise the limit and be more strict with enforcement like they are in the US. The limit going down to Florida from here is usually 65-75 but if you stray even a couple mph over that they will nab you.

 

Here you get those retards that will stay in the far left lane going 90 in a 100kph zone and purposely slow you down since they think they should control what speed you drive at.

 

I think 7" of lift is pushing it for the stock suspension geometry. You might want to look into the adjustable trailing arms.

I thought they did that to get out of the way of the buses that take up the far right-hand lane.... like Montrealers!