1978 Squealing Noise When Pressing Brake Pedal

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jakescervino
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1978 Squealing Noise When Pressing Brake Pedal

Post by jakescervino »

Hi everyone,

I have owned a 1978 Lincoln Continental Mark V for over a year now. The car has been running great so far with only some minor problems I had to fix along the way. However, I just recently had it oil sprayed. Since the moment I picked it up after the oil spray, the ALT light was on and the battery was no longer being charged. I replaced the alternator and the voltage regulator, and the ALT light has gone out and the charging system is working again. Ever since changing the alternator and both the alternator and power steering belt, now the car makes a squealing noise when I press the brake pedal ONLY AFTER A COLD START. The noise disappears as soon as I put it in gear and start driving.

Also, I live in St. Catharines, Ontario, and the weather here just started to get a little cold. The reason why I am mentioning this, along with the oil spray and belt change is that maybe one of these factors is the cause for why the car is now having this issue? There is no change of pressure in the brake pedal and it is still firm when I press it, and I don't see any brake fluid leaks. I have not checked the brake fluid reservoir yet, but I am assuming it is still full because the brake pedal still feels solid. Below is a video of the car making the squealing noise when I press the brake pedal after a cold start.

https://youtu.be/81zI0GGSA2E

I'd really appreciate it if someone could tell me what is causing the squealing noise and how it can be fixed.
Last edited by jakescervino on Mon Nov 01, 2021 5:52 pm, edited 1 time in total.
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TonyC
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Re: 1978 Squealing Noise When Pressing Brake Pedal

Post by TonyC »

That's very odd. It makes that noise when you press the pedal, with the car fully stationary, and goes away when you're in motion? I would think brake noise would happen only in a reverse scenario.

As I've never seen that happen before, I can only harbor a guess. If that did not exist until after this oil spray, it could be that the brake components were contaminated by the oil, like your alternator was. Maybe a close-up cleaning of the components and replacing the linings (the pads) may get rid of that; just remember to use silencing goo on the backs of the pads if you go that route.

If that turns out to be the case, it may be prudent to not make those oil sprays a routine-maintenance practice.

---Tony
"Don't believe everything you read on the Internet, just because there is a picture with a quote next to it." (Abraham Lincoln, 1866)
"Question Authority!"

1966 Continental Sedan, affectionately known as "Frankenstein" until body restoration is done (to be renamed "General Sherman" on that event)
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JimA
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Re: 1978 Squealing Noise When Pressing Brake Pedal

Post by JimA »

Check the tension on the new belt.
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thegermanfan
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Re: 1978 Squealing Noise When Pressing Brake Pedal

Post by thegermanfan »

You have most likely a hydroboost brake, which means your brake pressure is assisted by power coming from the power steering pump. V belt grooves were likely not cleaned after your oil spray. Those belt pulleys have to be free from any contamination. Also it is not uncommon that belts need re-adjustment after a short run-in-period.
1974 Lincoln Mark IV -triple black-
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thegermanfan
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Re: 1978 Squealing Noise When Pressing Brake Pedal

Post by thegermanfan »

You have most likely a hydroboost brake, which means your brake pressure is assisted by power coming from the power steering pump. V belt grooves were likely not cleaned after your oil spray. Those belt pulleys have to be free from any contamination. Also it is not uncommon that belts need re-adjustment after a short run-in-period.
1974 Lincoln Mark IV -triple black-
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