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1982 505S TD "Pepé Le Peugot" Squishy Breaks, Vacuum Booster leak?


Pepe Le-Puegeot

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Hi everybody!

This is my first post here. My name is Johanness in Portland Oregon. I just bought a '82 505S TD named "Pepé Le-Peugot"

He runs strong, and the manual transmission shifts well, with 120.200 miles on the odometer! The front brake calipers look a bit worn. And the pads are definitely low on meat and in need of replacement. I've ordered ​ some from a parts wholesaler via e-bay, and they should be here soon. Here are my braking symptoms.

When you come to a stop, after the engine has been at low revs, there is almost zero braking, and the pedal must be pumped. This pumping still may not yield much stopping power. However, if I downshift the manual transmission before a stop and the action increases the engine RPM, then there is more pedal, and more stopping power. The master cylinder is full, and the fluid in the cylinder looks to be of clean quality. The clutch works flawlessly as well. I don't suspect a hydraulic issues. I think it may be a vacuum leak?

When I shut the car off, I hear a hissing. It's the vacuum system taking on air.

I wanted to ask the pro's here before I head to NAPA to replace all my main vacuum hose.

Thanks guys!

-J

PS: here is a pic!

post-1722-0-03327600-1411234937_thumb.jp

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It sounds like you have a vacuum leak of some sort. Could be the plastic reservoir, one of the hoses, or even the brake booster itself. Rather than replace stuff randomly you need to find out were the hissing noise is coming from.

I would disconnect the booster and plug the hose and see if the hissing stops. If not, disconnect the reservoir and plug the hose.

Inspecting all the hoses and connections of course as well.

Rabin

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Rather than replace stuff randomly you need to find out where the hissing noise is coming from.

Yes. That is a very good idea. However, the vacuum hoses there, are very old, and cracked and need replacing anyhow. So as I go throughout the system replacing the worn hoses, I should hopefully find the leak.

I will report back.

Cheers!

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Good idea to do it as a matter of course, I just wanted to make sure you systematically checked for the leak rather than just start replacing things... :)

Hopefully it's something simple like a cracked hose or a hole in the vacuum reservoir.

Rabin

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So I have another question that also relates to the brakes.

I went to local Portland area Napa and Carquest auto parts stores. I went to inquire about brake pad replacement parts. Both stores didn't bring up any available parts.

As I mentioned before I was looking at this eBay auction: http://www.ebay.com/itm/320898013310.

I have not purchased these as of yet. The representatives that I spoke to at the Auto-parts stores, both said there were two types of front disk pads. How do you go about identifying what pads your 505 uses?

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Welcome to the Forum.

The front brakes are either Bendix or ATE. I've never had the Bendix ones, so I'm not sure how to tell you to identify them vs the ATE. It looks like those pads on Ebay are the Bendix type. Someone with more experience at both types may be able to tell you better but I would say if the hardware looks like this, it's ATE

ATE.jpg

If it looks like this, it's Bendix.

bendix.jpg

I generally get my brake pads from Rock Auto. They have a coupon code in the Vendor section of these forum.

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Thank you tulaweb.

I will take a front wheel off in a day or two and see what I find out. I'll try to shoot some pictures of what I find and post.

Also wanted to ask, does anyone know about these ported rotors i see on eBay? Looks like they are coming from Australia. Anyone have experience?

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The best brakes are solid high quality rotors, with very good pads. Cryo treated rotors are a plus, and if you find slotted rotors those are better than drilled holes. (Best braking is still solid rotors as mentioned). I will guess you have the ATE calipers simply because I've never had a 505 with Bendix calipers.

Your car has solid front disks, so the upgrade for your car would be to get 505 Turbo calipers and vented fronts disks.

They won't stop better - but they're pretty much fade free brakes.

Rabin

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For what it is worth, the only 505s I've seen with Bendix calipers are 1987-1988 ZDJL sedans.

The brakes on those cars never feel as solid as the cars with ATE calipers, which I think is due to the fact that the Bendix calipers are aluminium. Aluminum floating calipers are very light, but not as sturdy as a nice chunk of steel.

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Thanks for the replies friends!

I have ATE calipers ;-) and will now order proper ATE break-pads replacement.

Today I replaced all of the 10mm vacuum hose, and place upon new hose clamps. The squishy breaks symptom continue. I have more investigation to perform upon the vacuum system before certain that it is in fact not cause of the issue.

At speeds above 60kmph, there is a noticeable wobble coming from the front suspension. And seems to possibly be from the right front wheel. Question: Could this be a warped disk break rotor? Speeds above 120kmph the wobble resolves and the drive is smooth.

-Pepé

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One thing I have observed is that these cars are very susceptible to wheels being out of balance. A wheel weight falling off or mixing different lug nuts on one wheel will cause a noticeable wobble/vibration at middle speeds. A warped rotor would change in frequency at different speeds but wouldn't wait till 60kmph to start.

Do you have a vacuum gauge? Now that you have gone over all the hoses, you are probably left with the pump itself, the accumulator tank, or the break booster as the fault. Putting a gauge in the system and them clamping off each of those three items one at a time, may identify the fault(s)

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I'd also suggest checking bushings, ball joints and tie rods for any play. Any play in the front suspension can manifest itself as a shake or wobble at speed.

Dave's vacuum gauge test is a great idea - takes a lot of the guess work out.

Rabin

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A weak vacuum pump would require more rpms to power the booster, as you are seeing. Check the oil level in the pump. When the pump diaphragm leaks, the oil is quickly evacuated from the pump crankcase and burned. Then the rod bearing in the pump starts to wear, reducing the stroke, and the vacuum, and increasing the noise. The belt should be removed before checking the oil level so the pump will find its natural rest position. If rotating the pulley back and forth produces a clicking sound in the pump, the pump is probably beyond repair.

Repair parts are not available for the bottom of the pump, so it pays to replace the diaphragm on an old pump before it fails. The manufacturer says every 60,000 miles, although they generally last longer.

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One thing I have observed is that these cars are very susceptible to wheels being out of balance. A wheel weight falling off or mixing different lug nuts on one wheel will cause a noticeable wobble/vibration at middle speeds. A warped rotor would change in frequency at different speeds but wouldn't wait till 60kmph to start.

Do you have a vacuum gauge? Now that you have gone over all the hoses, you are probably left with the pump itself, the accumulator tank, or the break booster as the fault. Putting a gauge in the system and them clamping off each of those three items one at a time, may identify the fault(s)

Interesting. I will try to get to a tire shop and have then check the wheel balance.

I don't have a vacuum gauge. Mighty Vac would do the trick right? I can get one of those tools for around 30US.

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Interesting. I will try to get to a tire shop and have then check the wheel balance.

On my cars at least, and I think yours as well, the original lug nuts were two part swivel things and if over tightened they frequently broke. The replacements were one piece and a little longer. The replacements weigh more than the originals. If some of your lug nuts have been replaced, make sure each wheel has all one kind or the other. If the lug nuts are unbalanced, a tire shop can get the wheel perfect off the car and it can still be unbalanced when you put it back on.

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