denalilex
Full Access Member
hi all! let me first begin by apologizing if this topic has been addressed previously …. i’ve searched the internet for hours & for the first time ever - cannot find a single anything that refers to / addresses the issue i am having.
first - some background
i have a 2007 gmc yukon denali 6.2 v8 AWD
i recently (as in this week) just replaced both u joints on rear driveshaft
also removed & repaired both front brake calipers as PO never bled lines or lubed pins/slides. as you can probably guess, i’d had some sticky calipers, some seized everythings & tar in the brake lines .
with the repairs i also went ahead & replaced the flex hoses on both fronts & installed speed bleeders all around
my truck is still currently on jack stands as i’m having some serious issues bleeding the lines. but that’s not why i’m writing this post. they’ll bleed, eventually, it’s just being difficult & i have a scan tool capable of ABS bleed & have already performed that… MC needs bleeding so have plans for that tomorrow.
now for my main concern & reason for writing -
all of the sudden, when i shut the truck off & engine shuts down - im hearing a quick, audible grinding noise coming from the passenger side under the hood. i have no idea what this could possibly be. it’s definitely a grind & not a buzz, hiss, whine, etc. it doesn’t last long & it almost sounds as if something is grinding to a halt. i’ve considered idler pulley, alternator, etc etc but nothing seems to be showing any signs of faults. it doesn’t seem to be coming from my brake system area (MC , booster, etc) but i could be mistaken & don’t want that to be ruled out of any possible reason one of you may advise me to check it.
it’s concerning me & i don’t want to put my wheels back on & drive it obv til i figure out what’s going on.
for what it’s worth - there is absolutely air in the MC & subsequently, the brake lines themselves. & a good bit of it at that. i’m unsure if that could play a part in this issue. coolant is also somewhat low - i’m almost 100% positive this is from a slow leak that i found in the res that needs replacing eventually. within the last 3 months, i replaced all of the cooling system hoses & thermostat due to my plastic y connector at the heater hose splitting.
i also replaced the power steering hoses & power steering cooler. i do know one of the duckbill seals is bad & currently have something rigged up that has been working & stopped the leak that was coming from the bad seal. i will need to replace the seal eventually - it broke upon install. they’re a PITA.
sorry for the novel but hopefully that is sufficient background info to be able to draw some kind of hypothetical conclusion as to why i’m hearing this grind when i shut down my engine. i haven’t driven the truck in a little while due to needing to do some needed work on it so unable to report on whether or not it occurs under acceleration, stop, turns, etc. does. not happen at start up.
ill get a video in the morning if anyone would like to hear for themselves.
TIA!
*EDIT SOLVED*
i believe the grind had wound up to be brake system related.
if you’re interested in what all went into it … here’s a novel-ish length explanation . lol
i just completed the replacement of all my u-joints - i started hearing a god-awful squeak-screech that could have possibly been related to brakes but some of the symptoms were making me think i should check other components … the cyclic squeak did not start/stop when brakes were engaged so i started to stray away from them but front driver was locked up - again - so i knew something was also wrong with them. so i also just completed an entire rebuild & overhaul of just about every component related to my brake system & was having serious issues bleeding/purging the air out of .. well.. everywhere… as well as my pedal dropping to the floor despite multiple different troubleshooting attempts, gravity bleed, vacuum bleed, pressure bleed(built a DIY home depot weed sprayer pressure bleeder), ABS pressure bleed with my scan tool, tried to bleed MC on truck with no luck… wasn’t getting fluid to flow ANYWHERE… not even the master ports…so to no avail…decided to just pull my MC & bench bleed it even though i hadn’t ever run it dry .. process of elimination led me to do so…. turns out, my push rod was stuck depressed into the MC bore… one of the seals had the TINIEST little nick on the outer edge of its ring which allowed for a slow leak & eventual seized MC … i was able to extract the rod by plugging all of the ports / holes & using my compressor’s air hose nozzle to force it out…rebuilt the MC seal via a cast & mold(this was cheaper than a new MC & i searched for new seals but conveniently they’re impossible to find - even with part number) , honed the bore with 1500 grit(it was surprisingly in good shape. i just did so for preventative measure).. successfully bench bled MC, swapped all bleeders with speed bleeders, replaced all flex hoses, re-installed MC , re-bled ABS w scan tool… started her up & prayed…. the grinding noise was gone! the noise sounded like it emanated from passenger front. even while i stood in front of the truck & used my remote start to start & stop my engine… FWIW, i don’t know if this had any effect but i did lube/grease all pulleys as the fact that the truck had been sitting for a few weeks could have played a part… can’t definitively pin point the culprit but have narrowed it down to one of those few components.
thanks for all the input & suggestions …. i appreciate it ten fold. have had the truck back on the road & so happy about it. had been driving my f150 work truck that has no reverse … can get awkward at times lol.
first - some background
i have a 2007 gmc yukon denali 6.2 v8 AWD
i recently (as in this week) just replaced both u joints on rear driveshaft
also removed & repaired both front brake calipers as PO never bled lines or lubed pins/slides. as you can probably guess, i’d had some sticky calipers, some seized everythings & tar in the brake lines .
with the repairs i also went ahead & replaced the flex hoses on both fronts & installed speed bleeders all around
my truck is still currently on jack stands as i’m having some serious issues bleeding the lines. but that’s not why i’m writing this post. they’ll bleed, eventually, it’s just being difficult & i have a scan tool capable of ABS bleed & have already performed that… MC needs bleeding so have plans for that tomorrow.
now for my main concern & reason for writing -
all of the sudden, when i shut the truck off & engine shuts down - im hearing a quick, audible grinding noise coming from the passenger side under the hood. i have no idea what this could possibly be. it’s definitely a grind & not a buzz, hiss, whine, etc. it doesn’t last long & it almost sounds as if something is grinding to a halt. i’ve considered idler pulley, alternator, etc etc but nothing seems to be showing any signs of faults. it doesn’t seem to be coming from my brake system area (MC , booster, etc) but i could be mistaken & don’t want that to be ruled out of any possible reason one of you may advise me to check it.
it’s concerning me & i don’t want to put my wheels back on & drive it obv til i figure out what’s going on.
for what it’s worth - there is absolutely air in the MC & subsequently, the brake lines themselves. & a good bit of it at that. i’m unsure if that could play a part in this issue. coolant is also somewhat low - i’m almost 100% positive this is from a slow leak that i found in the res that needs replacing eventually. within the last 3 months, i replaced all of the cooling system hoses & thermostat due to my plastic y connector at the heater hose splitting.
i also replaced the power steering hoses & power steering cooler. i do know one of the duckbill seals is bad & currently have something rigged up that has been working & stopped the leak that was coming from the bad seal. i will need to replace the seal eventually - it broke upon install. they’re a PITA.
sorry for the novel but hopefully that is sufficient background info to be able to draw some kind of hypothetical conclusion as to why i’m hearing this grind when i shut down my engine. i haven’t driven the truck in a little while due to needing to do some needed work on it so unable to report on whether or not it occurs under acceleration, stop, turns, etc. does. not happen at start up.
ill get a video in the morning if anyone would like to hear for themselves.
TIA!
*EDIT SOLVED*
i believe the grind had wound up to be brake system related.
if you’re interested in what all went into it … here’s a novel-ish length explanation . lol
i just completed the replacement of all my u-joints - i started hearing a god-awful squeak-screech that could have possibly been related to brakes but some of the symptoms were making me think i should check other components … the cyclic squeak did not start/stop when brakes were engaged so i started to stray away from them but front driver was locked up - again - so i knew something was also wrong with them. so i also just completed an entire rebuild & overhaul of just about every component related to my brake system & was having serious issues bleeding/purging the air out of .. well.. everywhere… as well as my pedal dropping to the floor despite multiple different troubleshooting attempts, gravity bleed, vacuum bleed, pressure bleed(built a DIY home depot weed sprayer pressure bleeder), ABS pressure bleed with my scan tool, tried to bleed MC on truck with no luck… wasn’t getting fluid to flow ANYWHERE… not even the master ports…so to no avail…decided to just pull my MC & bench bleed it even though i hadn’t ever run it dry .. process of elimination led me to do so…. turns out, my push rod was stuck depressed into the MC bore… one of the seals had the TINIEST little nick on the outer edge of its ring which allowed for a slow leak & eventual seized MC … i was able to extract the rod by plugging all of the ports / holes & using my compressor’s air hose nozzle to force it out…rebuilt the MC seal via a cast & mold(this was cheaper than a new MC & i searched for new seals but conveniently they’re impossible to find - even with part number) , honed the bore with 1500 grit(it was surprisingly in good shape. i just did so for preventative measure).. successfully bench bled MC, swapped all bleeders with speed bleeders, replaced all flex hoses, re-installed MC , re-bled ABS w scan tool… started her up & prayed…. the grinding noise was gone! the noise sounded like it emanated from passenger front. even while i stood in front of the truck & used my remote start to start & stop my engine… FWIW, i don’t know if this had any effect but i did lube/grease all pulleys as the fact that the truck had been sitting for a few weeks could have played a part… can’t definitively pin point the culprit but have narrowed it down to one of those few components.
thanks for all the input & suggestions …. i appreciate it ten fold. have had the truck back on the road & so happy about it. had been driving my f150 work truck that has no reverse … can get awkward at times lol.
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