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!

I would start with checking:

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

Engine mounts,

Vacuum.

Good luck,

Sam

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.

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

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!

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.

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!

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

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!

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-Caliper-Silicone-Formula/dp/B000HBGKH4

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.

"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

Thanks Mike, but what about this?

http://i16.photobucket.com/albums/b8/rogersb/CamryBrakes/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

"http://redirectingat.com/?id=252X400&test=off&url=http%3A//i16.photobucket.com/albums/b8/rogersb/CamryBrakes/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

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/ubbthreads/showflat.php?Cat=&Board=UBB10&Number=447637&fpart=&PHPSESSID=)

for your headset, and this thread:
winter maintenance notes (http://www.thumpertalk.com/bike/ubbthreads/showflat.php?Cat=&Board=UBB10&Number=418551&fpart=&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/productpages/waterproof.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.thumpertalk.com/forum/archive/index.php/t-69837.html)

http://www.belray.com/consumer/productpages/waterproof.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 (http://www.automotivehelper.com/topic431704.htm)

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

Sounds like you might have a bad brake hose or caliper or both. Try jacking up the front end and having someone in the driver seat hit the brakes and let up and you try to turn the wheel. If the wheel is hard to turn then gets slightly easier, open the bleeder and see if it gets any easier. If it DOES you have a bad brake hose. Servicing a caliper is not recommended if you don't know what you're doing, they're pretty easy to mess up and i'm not sure they sell rebuild kits. A lot of times the bore that the caliper piston sits in gets corroded over the course of years and there isn't much you can do about that short of replacing it.

Thank you very much usedranger, you sure took a lot of time helping :). I ended up with the Permatex 24115 silicone formula, the one I linked.
I managed to take out the piston by connecting it back to the brake hose and pushing it out. No corrosion at all, nothing wrong with it, as far as I'm concerned. I cleaned it up and reassembled it, mounted everythig back on the car ... and surprise ... no change :(
I'll check the brake hose next as RahX suggested.

"mounted everythig back on the car ... and surprise ... no change"

There will not be any change if the rotor is warped, until that rotor is resurfaced or replaced. Did you check and/or relube the slide pins on that caliper?

Mike

You said there are issues with your landlord prohibiting working on the car, but as MikeG and others have said you need to get the rotors trued up. Either take yours in and have them turned or get a new set [make sure the store tests those to make sure that the new ones are ok;). Then reassemble BOTH sides, {replace both sets of pads, clean and lube slides etc}. If your brakes are working properly then you can begin to tackle the "vibrations... and shuddering" that you have mentioned, which may turn out to be an entirely separarte problem from your brakes. Also, have you checked for any leaking at the Master Cylinder, or booste?.

As suggested in a past response, Wheel balance may be a good start although there is a cost to that. Start by looking to see if the weight has fallen off one of the wheels (no cost:)there and even the landlord can't object to that.!

Then get a buddy to start the engine and you poke your head under the hood;watch to see if the engine moves if he has his foot on the brake and puts it in gear. Use something like a board or rod as a fixed reference point front - back, side-side. Good luck.

Ok, here's another update on the matter. I changed the rotor about 2 weeks ago and nothing changed. I also realised that after the wheel gets hots and starts vibrating (which now happens regularly after 30 min on the streets and sooner on the freeway), I must unscrew the bleeder plug on that wheel. Once I start doing it, brake fluid rushes out in a small jet. Then I'm good for another 30 min :)).
So I assume you all agree that it's the brake hose or brake line. I tried to get them off but I'm having a real hard time with those cheap alloy 10 mm fittings, they start to round when using a wrench on them. Any suggestions, on how I could unscrew them for inspection?
Another thing: I followed the brake lines, and the front driver brake line is short and connects to a 3 way manifold right next to the master cylinder. The front passenger brake line connects to a manifold towards the middle of the engine compartment. This is a 5 way manifold with one line going directly to the brake cylinder and a second one going to that first 3 way manifold; I assume the remainig 2 lines go to the rear wheels. It doesn't look like such a smart system, I believe it has more pressure on the front driver brake line even when working properly.

Thanks again for the help.

Sounds like there may be an obstruction in the brake line. Loosen the "banjo" bolt using a box-end wrench or a 6-point socket wrench. If worse turns to worst, douse it with pentrant, and use some vise grips on it.

Now that I think about it, the obstruction may be that rusted banjo bolt itself. If that is the case, then your probably going to end up buying a new caliper and brake hose...about $40 total. No need to fight that bolt, just unbolt the caliper and disconnect the hose from the brake line. Replace and relube all the sliding pieces.

Get the rotors turned to true them up. Any warpage from the bad caliper will remain. The landlord will have to suffer a few hours of a car w/o wheels. Just be sure that you use drip pans to catch any fluids.

I'll throw the note in that Toyota uses sliding pins that have rubber rings around the ends to help with centering them in the caliper holes. Over time they can swell up and prevent the caliper from sliding freely. Auto parts stores don't sell them and they don't come with newly bought pins. For just a few extra bucks (seriously), buy new pins with the rubber ends from the dealer.

Reinstall the rotors, caliper & hose and scuff the pads to prepare them to accept the new rotor surfaces. Finally, flush that brake fluid with new fluid to get rid of the absorbed water. I'd say to replace the other caliper and hose, too, since it is likely affected as well. But you could save it for another sunny day knowing it needs to be done in the near future.

Good luck!

That rubber brake hose may be collapsing internally and not allowing the brake fluid to flow back away from the caliper. This would mean the caliper would always be putting some pressure on the pads and hench the rotor. After a period of time the rotor warps from the heat it is experiencing. I have to agree with jdmccright. It's time to replace the caliper and brake hose on that side.

Mike

I changed the brake hose and nothing changed. Damn it! I used a flare nut wrench and after many tries, I was able to finally loosen the fasteners, the one next to the brake hose was a PIA. Is the banjo bolt the one that connects the brake hose to the caliper? If positive, that one was no sweat with a 14 mm 1/2 in socket and a breaker bar, I loosened it previously when I took the caliper apart.

Could some one please check their 99 Camry CE, no ABS, US model for similarity with the brake line setup in my previous post? Thanks.

I was able to run a wire through the 3 way manifold and through the brake line segment that connects the master cylinder to that 3 way manifold (it connects to the first piston, the one next to the brake booster), so they're off the hook.
The brake line segment between the brake hose and the 3 way manifold is rather long and I couldn't run the wire wire through, but it went in a little bit more than halfway from either end. I'll have to mess more with that one.
I assume that with a faulty master cylinder I'd get pressure in the passenger caliper too, right? I did some reading on how stuff works, and the previously described brake line arrangement is weird, I doesn't have 2 circuits.

Thanks for helping, posting and reading!

I'll repeat what's been said but haven't heard you do yet...get the rotors turned to eliminate any warpage and either re-lube the slide pins or get new ones. If the pins don't go in & out easily when greased, get new ones. Also, see my note above abt the rubber rings on them.

A pump or two of the brakes with the bleeder open would prove or disprove a blockage in the system upstream of the brake hose.

You mention having trouble getting a caliper piston out to inspect it. It should come out easily with a pump of the brakes or compressed air. The caliper surfaces can look fine but if the piston is cocked in the caliper bore it will hang up and not retract...usually due to uneven caliper wear or misaligned pads due to rust formation.

Better late than never, but I have to tell you I fixed the brake pressure issue. It's been 3 months already, but at least I had time to make sure it works.
It wasn't the rotor, caliper, brake hose or brake line - IT WAS THE MASTER CYLINDER. What exactly was it inside of it I don't know, I don't feel like taking apart that SOB, I just replaced it.
I guess it only affected the front driver's side caliper because of the bad design of the brake line circuit (as I mentioned in an earlier post). If I had more confidence in this car over the long term, I'd redo the circuit to a more conventional/simple layout.
Thanks to all of you posters for bearing with me!

Thank you for the feedback on the problem.