99 5sfe - weird brake vibration and engine vibration

[zorobabel]

Hi, I hope some of you can help me a little bit with this.
This is the problem: sometimes the car starts shuddering on the freeway in or out of gear (it's a manual gearbox) and it is felt thouroughly through the brake pedal, exactly like you'd feel the abs kicking in. It goes away after a while, or it keeps doing it longer, but usually after a stop, it goes away.

There also seems to be an accompanying noise from the engine, brake pedal pressed or not, especially felt at 60mph, but also higher. Like there's something engaging the brake in a pulsating manner, while I'm not pushing the brake. Like short kickbacks, or like misfire or something, I'm really not sure how a misfire would be felt. It starts easy but gets worse as I drive (like gases acumulating?). The engine in this car also vibrates above 2000 rpm to about 4000 rpm. The weird thing is that when it's doing the shuddering thing, it doesn't seem to vibrate the same way as usually.

Some facts about the car: CE trim, in practice it doesn't have ABS, and I don't think it was equipped with ABS (I didn't notice the sensor when working on a front wheel).
I bought the car at about 148k at the end of November 08, back then I had only a few shudder occurances.
I changed the oil, filter and sparkplugs (walmart supertech syn 5w30 and NGK BKR6ES-11) at 150k, and drove 4000 miles (road trips) in December and begining of January without a single shudder occurance. I also changed the pcv valve at some point. Then as I was aproaching 155k, it started to shudder again up to the point when it shudders almost everyday I go on the freeway.
I put some seafoam in the engine oil, and drove it 15 miles, then I changed oil and filter at 155k (2 weeks ago). Unlike the 150k oil change, the shudder didn't go away this time.
I'm pretty sure it's got something to do with vacuum, and perhaps ( I hope not, something fishy with some valve).

What should I check next? I know there's some more valves involved, but I'm not a mechanic, and I'd apreciate all the help.

Thanks a lot!

[somick]

I would start with checking:

Wheel weights (inspect the wheels for a clean spot where they usually are),

Engine mounts,

Vacuum.

Good luck,

Sam

[usedranger]

Jack up the front end. remove the wheels. Check for loose brake parts; pads, caliper. Check the tie rod ends ;can you move it up and down easily. Check CV joints; torn boot, loose excessive play. Check the stabilizer bar for excessive play; ie can you easily move it.
If you don't find anything obvious, I would suggest taking it into a trusted mechanic. "weird vibrations" are not a good thing.

[Mike Gerber]

I would also check the front brake rotors for excessive runout. A warped rotor could be causing the sysmptoms you describe. It could be contacting the pad(s) creating excessive heat and warping even further at highway speeds. You said it goes away after a stop. That could be just enough time for the rotor to cool a bit and have some of the warpage go away. Just a hunch here.

Mike

[jdmccright]

Along with warped rotors, I'd look at sticking caliper slide pins and/or brake caliper pistons, though the latter rarely happens on both sides. Sticking pins results in uneven wear between inner and outer brake pads. Sticking caliper piston results in cock-eyed wear on both inner and outer pads.

Most of the time, rotor warpage is caused by misadjustment of the rear drum brakes, causing the front ones to do most or all of the braking. Good luck!

[zorobabel]

Ok guys, you were right, it's the brakes.That's good, at least it's not something worse.
Thanks for the hints and the replies!
Two days ago I had to replace the brake pads on the front driver side wheel. They were perfectly even, so it's definitely not the sliding pins. Now with the new pads, the problem got even worse, and I noticed the wheel is hot again.
I'm thinking of taking out the caliper and look at it, it's definiteley dragging. I wanted to do that tonight, but I couldn't find "Lithium soap base glycol grease" as per manual. I looked at walmart and autozone. The best I could find was some CRC synthetic grease (that had written on it do not use on caliper pistons) that looked good up to 600F at 10$. Where do you guys get the "Lithium soap base glycol grease"?

Thanks

PS You're definitely right about the rotor, but I want to make sure it's not the caliper first, there no sense in ruining another rotor. And frankly, I could live with some vibration when braking, but having vibrations on the highway is just too much. And I've driven a rental with warped rotors, but they only bothered me when braking. At least my rotor doesn't cause vibration when it's not hot.

[usedranger]

Thanks for the post on your results. It seems confusing, to me anyways, That you say "with the new pads, the problem got even worse, and I noticed the wheel is hot again." Seems the problem has not been solved. I will assume that you changed both sides[driver &passenger] pads. What was the condition of the other set? You also say "no sense in ruining another rotor". Was the rotor groved or otherwise ruined? When you apply the brakes does it seem like the car is riding on oval shaped tires?

I also had the thought that you are saying you are planning on taking the caliper apart...is this what you mean by "thinking of taking out the caliper".

Did you have time to check the other components as suggested in the above posts? Wheels balanced? Check the struts? Have you had the motor mounts checked out? I might suggest doing some of those first. Good luck!

[Mike Gerber]

You don't need to remove the caliper to see if it's dragging. Just jack up the front of the car, place the transmission in neutal and try to rotate the wheels by hand. If one is noticably harder to rotate than the other, you have found your offending caliper. It's usually not the caliper piston hanging up (although it can be). It's usually the caliper slide pins that are causing a caliper to hang up. If this is the case you will have to remove them, clean or replace them and regrease them before reinstalling them. The synthetic brake grease you mentioned you saw at an auto parts store is perfect for relubing the caliper slide pins.

My vote is still a warped rotor. You might want to take those off and bring them in to be resurfaced. You should have done that when you installed the new pads. Do that now and you will find the offending rotor. We'll assume there is enough meat (thickness) left on the rotors to cut them. Just lightly sand the surface of the pads before reinstalling them. This gives the pads a new surface to seat to the freshly cut rotors. Make sure you put the pads back on the same position they were removed form.

Mike

[usedranger]

I agree with what MikeG has said. However, and I just might be a bit slow this morning, but I could not figure out if you replaced just the pads and put the "ruined" rotor back on or what. You have mentioned vibrations when driving and not braking, and I was not clear if you are talking about a pulsating feel as you mentioned in the original post it was "exactly like you'd feel the abs kicking in" or a vibration caused by something else like a broken motor mount or out of balance wheel. But at this point, since you are focused on the brakes, making sure those are assemled correctly, slidepins are cleaned and lubed, and that the rotors have been trued up should be a start. I will confess ingnorance here but are there anti-rattle clips in your brakes? If so check and make sure those are installed. While the brakes may be part of your problem, I hazard a guess the virbations have another cause in the suspension or steering. Good luck!

[zorobabel]

Originally Posted by Mike Gerber

You don't need to remove the caliper to see if it's dragging. Just jack up the front of the car, place the transmission in neutal and try to rotate the wheels by hand. If one is noticably harder to rotate than the other, you have found your offending caliper. It's usually not the caliper piston hanging up (although it can be). It's usually the caliper slide pins that are causing a caliper to hang up. If this is the case you will have to remove them, clean or replace them and regrease them before reinstalling them. The synthetic brake grease you mentioned you saw at an auto parts store is perfect for relubing the caliper slide pins.
Mike

Ok, I jacked up the car and I could feel the driver side wheel a little harder to rotate. If that wasn't enough, with the transmission out of gear the driver wheel doesn't rotate when starting the engine (actually it started to rotate but quickly stopped as the rpm's went down). Also, in 5-th gear I accelerated to about 60 mph, then quickly put the transmission out of gear and jumped (that sounds weird ). The driver wheel stopped pretty quickly while the passenger wheel continued to rotate as normal (when out of gear). So there's a drag, But like I said, I don't believe it's the sliding pins, as I just checked them when I changed the pads, and the old pads were worn evenly.

I found this "Permatex Ultra Disk Brake Caliper Lube Silicone Formula, 8 oz" for 13$ at pepboys, what do you guys think? (for caliper pistons)
http://www.amazon.com/Permatex-24115.../dp/B000HBGKH4

[zorobabel]

Originally Posted by usedranger

I agree with what MikeG has said. However, and I just might be a bit slow this morning, but I could not figure out if you replaced just the pads and put the "ruined" rotor back on or what. You have mentioned vibrations when driving and not braking, and I was not clear if you are talking about a pulsating feel as you mentioned in the original post it was "exactly like you'd feel the abs kicking in" or a vibration caused by something else like a broken motor mount or out of balance wheel. But at this point, since you are focused on the brakes, making sure those are assemled correctly, slidepins are cleaned and lubed, and that the rotors have been trued up should be a start. I will confess ingnorance here but are there anti-rattle clips in your brakes? If so check and make sure those are installed. While the brakes may be part of your problem, I hazard a guess the virbations have another cause in the suspension or steering. Good luck!

Sorry for the confusion, let me make things a bit clearer.
I only replaced the front driver side pads as they started grinding, and my landlord doesn't allow car work - I did a quick clandestine fix in the evening. I never took the rotor out, but I was reffering to the current rotor when talking about the ruined rotor in the other post. It was not miror finish, but it was in pretty good shape. I'm saying that's ruined because now with the new pads the freeway vibration (when it starts) is also felt in the steering wheel, so I'm pretty sure the rotor gets hot and the warping is exacerbated, causing the vibration - it's still a weird one, nonetheless, but it's "exactly like you'd feel the abs kicking in". It's also felt when braking, once it starts. All the brake components are in place. I'm thinking on getting the piston out of the caliper and look for trouble spots, then re-lubing it, and wish for success.

I'm pretty sure it's the brakes now, and I haven't checked some of the things kindly suggested in the other posts. I haven't checked wheel balance, I am 100 % sure I need to replace the front strut mounts - as this is a common problem for this year, and I can feel in spine that my car car is affected; the rear motor mount is the only one left to replace, and I'm pretty sure it needs replacing. I plan on doing the rear motor mount in 2500 miles when I'll change the oil, and hopefully do it in friend's garage; it seems it's pretty hard to take out, and I have some medical problems, but I'm getting better.

[Mike Gerber]

"I only replaced the front driver side pads as they started grinding,"

Did you replace the passenger side pads at the same time? If not, having a mismatched set of pads on the 2 front wheels is not a good idea. Different sets of pads can grab differently, causing some unusual braking characteristics. That said, that's not your original problem.

"I'm thinking on getting the piston out of the caliper and look for trouble spots, then re-lubing it,"

You don't lube the caliper piston with anything other than fresh brake fluid. That's used more as a lubricant to help it slide back in to the bore. Don't use the disc brake caliper lube here, although it's a good product to use for the caliper slide pins.

Mike

[zorobabel]

Thanks Mike, but what about this?

http://i16.photobucket.com/albums/b8...es/Brake11.jpg

There it says grease should be applied to those points, which include parts in the caliper...
I'm having a hard time getting that piston out any way.
Thanks

[Mike Gerber]

"http://redirectingat.com/?id=252X400...es/Brake11.jpg"

Interesting. I have seen that in the manuals before but have never really paid attention to them showing putting some type of grease on the piston itself. Maybe because this grease (which nobody can ever find) is a soap based grease, it will discolve in the brake fluid. If it were me, I would still only use brake fluid on the piston to relube it prior to reinstallation. That is assuming you can get the piston out. Most people use compresed air from the backside, blowing it through the hole for the bleeder screw, to remove the piston. The other areas shown in the picture are the caliper slide pins and I would definitely put synthetic disc brake grease on them. Hopefully someone else reading this post can comment here.

Mike

[usedranger]

These notes are some from other forums on grease;

""grease, now that's a topic worth a few thousand words...

first some info... grease consists of two components, the 'carrier' and the 'oil'. heat causes the carrier to bleed out the oil, which then lubricates the local metal surfaces. there are several popular carriers, the two most prevalent are lithium and aluminum. the properties of a given grease are dependent upon both the carrier and the oil. lithium based greases are popular for their low cost and wide range of applications. newer lithium complex based greases also rival aluminum based greases for water repelency. in some cases, additives such as moly are added to the grease to increase severe service lubricating properties. by the way, greases are evaluated using a standardized suite of ASTM tests, which then allows for apples-apples comparison between types and brands. one other way to find a good grease is to have a conversation with the equipment maintenance folks at a coal mine. :*)

in short, use a quality grease which has good water repelency and good Timken 'OK' and '4-ball' ratings.

for your linkage/swingarm, read this thread:
linkage teardown notes (http://www.thumpertalk.com/bike/ubbt...rt=&PHPSESSID=)

for your headset, and this thread:
winter maintenance notes (http://www.thumpertalk.com/bike/ubbt...rt=&PHPSESSID=)

other notes...

CRC/Sta-Lube STA-PLEX lithium complex grease (shown in the pics in my links above) has a higher Timken 4-Ball rating (ASTM D-2596), higher Timken OK Load (D-2509), and better water washout resistance (ASTM D-1264) than many more expensive greases, even Amsoil's $11/tub synthetic racing grease. best of all you can get a 1 pound tub of STA-PLEX at Pep Boys for around US$3.59.

Bel-Ray 'waterproof grease' is an aluminum complex grease, and for the most part aluminum bases provide the highest water repelency/washout resistance available. bel-ray's web page (http://www.belray.com/consumer/produ...aterproof.html) doesn't provide any ASTM test data.

jim aka the wrooster""


Try these links as well;
http://www.thumpertalk.com/forum/archive/index.php/t-69837.html

http://www.belray.com/consumer/productpages/waterproof.html

And Mike G and Brian may rember this link as they discussed this way back in '05;

http://www.automotivehelper.com/topic431704.htm

Also a tech sheet for CRC Lithium-soap-based grease;
http://www.farnell.com/datasheets/102295.pdf

In the end for what you are doing a Lithium Brake grease avalaible at most auto stores would probably serve you well. In my brake rebuilding, including a few calipers, I have used Sil-Glyde made by AGS. I have not had any problems with it.
According to that manufacturer:
100% pure silicone formula that can be applied to the entire brake assembly. Prevents brake squeal that can occur in metal-to-metal contact. Also increases brake-life by protecting and lubricating all critical braking components.
100% pure silicone formula that can be applied to the entire brake assembly. Prevents brake squeal that can occur in metal-to-metal contact. Also increases brake-life by protecting and lubricating all critical braking components.
100% pure silicone formula that can be applied to the entire brake assembly. Prevents brake squeal that can occur in metal-to-metal contact. Also increases brake-life by protecting and lubricating all critical braking components.

Good luck!