Hey all! I am a new member, just posted in the newbie area if anyone wants to say hi or talk off topic.

Gotta make this short because of work stuff but basically my brake pedal is very stiff to where at stop lights I have to brace against my seat back in order to keep the car from moving just from idle power. The brakes work great, they just take a lot more pressure than they should in order to stop the car. I failed my Hawaii safety check today, the guy got in, drove 10 ft, got out and told me to fix that before he even looks at the rest of the car.

It looks like it might be the brake booster judging by some quick research here on the forum. I'll put some links below to what sound like similar issues. And yes, I do have the check engine light on but I forgot the codes. I will look them up again when I get home later and update this post. Can anyone confirm that's what it is or suggest any troubleshooting tips to confirm or eliminate possible issues? Thanks in advance!

~Evan

https://www.jaguarforums.com/forum/x...failure-84009/
https://www.jaguarforums.com/forum/x...-valve-105039/
https://www.jaguarforums.com/forum/x...y-stiff-97895/

 

Hello-Ha, Evan,

Sorry to hear your woes and troubles, Thermo has posted on the thread links you mentioned and he is No1 in my view.

If you have the time, I'd post your codes and we can go from there!!

Good luck, Stu

 

Very hard pedal is almost always something up with your brake booster(the big round black canister looking thing behind where you put brake fluid in the fluid tank) but before you change it out, make absolutely sure since it works off of engine vacuum that you don't have a leak somewhere on the hard plastic line that goes from the engine to the booster.

Here is a pretty good post:
https://www.jaguarforums.com/forum/x...ication-37354/

 

ekuest, aloha brudah. Odds are, you problem is simply a stuck check valve on the line running from the top of the engine to the brake booster. That can take away all the brake boost and leave you with a hard pedal. You can try removing the tube and replacing it with a temporary hose to see if you get more pedal back (may not be perfect, but it should be better). Also, you can see if the pedal feels different with the engine running and not. If it does, then the check valve is working and your problem lies in the ABS module, not the brake booster. If the feel is the same, then you have either a bad check valve or bad brake booster.

I used to live on Oahu, across the street from the airport. Granted, back then, I was driving around in a lifted green expedition and did a lot of time playing around up on the north shore at Keana Point. I am looking to get back there one of these days, but to Maui and some of the other islands.

If you need any more help, let me know.

 

Yeah that thread title should say "stiff" somewhere in there but I can't figure out how to edit it. EDIT: YAY I can edit now!

Thanks for the input everyone! The codes are p0171, p0174, p0430, and p0456. I think it feels pretty much the same with the engine running or not. I'll check tomorrow.

One thing I noticed is that the first time I hit the brakes after some highway driving or something where I haven't been braking for a while, they will initially feel pretty good and the pedal won't resist me. Then after that first time it will get stiff again.

Nice to meet you think and thanks for the help Thermo! Funny that you used to live here too. At one point I lived in Aiea by Pearlridge mall and I also lived in salt lake kinda near the airport.

Got a busy day tomorrow but the weekend is pretty free so I will post an update when I get a chance.

 

ekuest, the P0171 and P0174 are vacuum issues. It is very possible that the vacuum line running between the manifold and the brake booster has a crack in the "football" in the center of the line. Rub the center piece (it is a check valve). If the plastic seems like it is turning to powder, get yourself another line and then see how your brakes are. It may be something as simple as that check valve is having issues and it is not building up the vacuum for the brake assist. So, after a long drive (H3 is always a fun drive coming out of Kahlua), the check valve has "leaked enough" that the brake booster has a full vacuum. But, after a few steps on the brakes, the vacuum is gone. After that line, I would next check the PCV line hose (look to the left of the throttle body, the line is about the size of your thumb). Look on the underside of that hose and see if it is split. If you have a ribbed hose (the original hose was smooth), then this is almost garanteed to not be an issue. If you have a smooth hose, check it. that is another common issue we have with our cars.

I used to live in the military housing (on Dickson Street). Granted, by now, where I lived has been bulldozed and new housing has been put in. They were starting it as I was leaving. If you ever need any body work, one of my friends owns a body shop on Kaihikapu Street. As you turn off of Mapunapuna on to Kaihikapu Street, it is the second building on your left. Tell him Thermo sent you and I am sure he will have a surprised look on his face. If he doesn't remember me, ask him about the guy from the Ford Truck group that had the lifted Expedition. That should spark his memory. Granted, this is assuming he still has the business. He was one of the best body shops on the island.

 

Hey sorry guys, thought it was going to be a free weekend but the gf had a friend visiting so we had to play tour guide. Free now though so getting to work. Thanks everyone, especially Thermo! So I checked out both of those lines but didn't notice anything wrong with either. I circled the ones I looked at in the picture below to make sure I got the right ones. I tried braking with the car on and off and what i found was that with it off I couldn't even drepress the pedal more than an inch or so, and with it on I could depress it all the way to the stop, but it took a lot of force and moved really slow because of the resistance. Not sure if that helps.

Also, I'm putting a picture of my fender below, think your guy could repair that Thermo? I know it's a pretty bad one...

 

I'd try pulling the line out of the vacuum canister and with the car running put your finger over the end of the line and see if you have a good strong vacuum coming off the engine. If so, it's time for a new vacuum canister, if not you've got a vacuum leak somewhere or the check valve is shot.

You've got me wondering, did this problem start right after you changed the brake pads? If so, it may actually be the master cylinder not the power brake booster as sometimes the internal seals get damaged when you push the pedal all the way down to the floor a few times after a brake job as they haven't traveled that far in quite a while and there may be corrosion or crud in the bottom half of your master cylinder that can cause them to fail.

That fender is certainly fixable but you may want to remove it from the car to get the dent out.

 

ekuest, oh yes, he can get your fixed up no problem. That isn't that bad. Worst case, he replaces the fender. NOt that big of a deal.

As for your brake issue, let me think about this for a moment and see what I can come up with.

 

Yeah ltmax, as the title states they were fine up until I changed my front brake pads. The old pads were completely gone when I bought the car, so something like what you're describing sounds very feasible as I had to push the pistons in quite a bit after I got the new pads on. What line do I pull out of where? Can you show me on a picture? What's a vacuum canister? That big brake booster cylinder?

If the vacuum was leaking, I would probably hear it right? I do hear some hissing-type sounds coming from the engine, but very faint and I havent been able to pinpoint it. Seems like it should be a pretty loud hiss if that was the issue. Thermo, you said that I can just put in a straight hose in place of the line with the check valve from the intake manifold to the brake booster. That won't screw things up not having the check valve there? I dont want to cause more problems trying to troubleshoot this. I was thinking about just taking it off and blowing in each end and seeing if it checks one way but not the other or if it leakes by one direction.

As for the fender, a body shop near me said they wouldn't touch it and recommended replacing the whole fender. That was ~$1000 and the whole car cost me that much so I said no thanks. If I could get it banged reasonably straight for under $300 I would consider it. Any more than that and it's just not worth it to me since it's purely cosmetic.

 

It's where the hard plastic line from the engine/check valve plugs into the big black cylinder behind the brake fluid reservoir. In the first picture you posted it's up in the top right corner.

 

ekuest, you are looking at the correct lines. As for what is causing your problem, I am somewhat stumped. It would almost appear to me that you have an issue with the ABS module (behind the passenger headlight). It isn't porting the brake fluid properly to the calipers. That is leading to the high resistance that you are seeing. Granted, I have a silly question, do you have a Check Engine light on? Is your speedo acting properly? I only ask this as it kinda sounds like the car is seeing a wheel (or two) not spinning and it is trying to engage the ABS system and not apply lots of pressure to the brakes.

 

ltmax, how do I unplug that line? I don't see any clips or anything and I am afraid to just start yanking on it. If there was no suction on that line then wouldn't there be not enough vacuum in the header and the engine wouldn't work or would at least run rough?

Thermo, what makes you think it's abs and not the vacuum brake assist? I do not know much about either but I'd like to rule out the vacuum assist part first since that actually makes a little sense to me before I start troubleshooting the abs system which is pure wizardry to me. Oh and yeah the check engine light is on. I posted all the codes somewhere above.

 

To pull the line off you just pull on it, it's just pressed into a grommet and into the power brake booster. Just take your time and be gentle enough not to break the plastic line. Once the end is out you can rotate it around to get at it and check for a good vacuum signal.

I think you're going to find that you've either got a bad vacuum leak (something up with the hose/check valve, or big vacuum leak on the engine like intake manifold o-rings or broken hose) or more likely you have a good strong vacuum signal and that will confirm that you need to replace the power brake booster. If you do, I'd recommend putting a new master cylinder in at the same time so you don't have any more trouble down the line as they are pretty cheap and it's got to come off to get the booster out anyway.

One more real easy thing that may be causing your problem, one time years ago I had a guy bring me his car after he did a brake job and you had to step on the brake pedal with all your might to get it to stop, it turns out he mistakenly put the pads in backwards and the metal on the brake shoes was pressing on the rotors and the pad material was on the caliper side. Might be worth giving your pads a quick look over and just make sure that's not the case.

 

Haha wow! I hope I'm not that braindead, but I will be sure to check when I get home tonight. Seems like you would get some pretty bad grinding or squealing noises with metal on metal braking like that.

Also, I did post the codes way above (p0171, p0174, p0430, and p0456). Do those tell you guys anything? It looks like the 0171 and 0174 are both indicative of running too lean which could mean poor vacuum right? So maybe it's not the brake booster or the brake booster hose but the manifold or intake hose like you mentioned above? I would think I'd hear a loud hissing coming from wherever the vacuum leak is but I haven't been able to find anything yet. What about the other two codes? 0430 seems to be something about the HO2 sensor or catalytic converter and I can't find anything for 0456. There is a plug that is disconnected (see right below the "L" in "Looks OK" pointing to the brake booster hose) but I can't find anywhere to connect it to so I thought it was just for an optional accessory I don't have.

I do also have the "Cruise Control Not Available" and hesistation when accelerating quickly issues that seem to be pretty commonplace now that I am researching more around the forum. Cruise control does always work, it just says it doesn't. The hesitation is that when I floor it off the line, it sputters once or twice and then shoots off. Other than suddenly flooring it, I have no such problem.

EDIT: I just realized that any time I've listened for a vacuum leak the car has been at idle. If I had someone step on the gas while I stick my head under the hood would the vacuum leak (if there is one) be louder and therefore easier to find?

 

ekueast, P0171 is a vacuum leak on the Bank 1 Side (ie, side nearest the firewall). P0174 is a vacuum leak on the Bank 2 side (nearest the radiator). Normally, when you have both of these, you are looking at a problem with either the PCV hose leaking (but you have the new style, so, not likely), or your IMT valve o-rings are bad and they are looking (look on the end of the intake manifold nearest the passenger front wheel, those black circles you see are your IMT valves). Put some new o-rings in and see what you have then. These o-rings are common issues and they are pretty easy to install (1 tidbit of info though, the bottom one you will not be able to remove the IMT valve with the intake manifold installed in the car, but you can remove the IMT valve slightly and then stretch the new o-ring over the end of the valve to fit it on).

From here, I would say to find someone that smokes a cigar and blow some smoke around the engine bay when the motor is cold (so the fans are not running) and see if you can spot a vacuum leak. It is possible that either your upper and/or lower intake seals are failing and they need to be replaced.

From there, you are going to want to clean your MAF sensor. This is easy. Get your hands on a can of MAF sensor cleaner and pull the MAF sensor out of the intake (next to battery box) and squirt a little fluid in there. Big thing to keep in mind is you don't want to spray straight down the hole. You want to bounce the fluid off of the walls of the MAF sensor so you don't damage the wiring inside the sensor).

If you do all this, then I would say to then disconnect the battery to clear the codes (unless you have a code reader, then clear them that way). This should get rid of your P0171 and P0174 codes.

As for the P0430 code, that is saying that your Bank 2 catalytic converter is not working like it should (ie, not removing enough of the bad gases). It may be possible that the P0171/174 issue is causing this. So, lets see if that is the cause. If not, then you are looking most likely at either a bad O2 sensor or your cat is failing.

As for the P0456 code, that is saying that you have a small leak in your gas tank and the system can not draw a sufficient vacuum to meet emission requirements. Normally, this is simply the gas cap is either not on tight enough or the o-ring on the gas cap is failing and you need a new gas cap. if that doesn't fix it, then I would say to open the hood of your car and locate the purge valve (on the firewall, between the brake booster and the intake manifold, it will have a vacuum line running to it). Remove it from the car and then using a little bit of carb cleaner, spray the cleaner into both ports of the valve and flush it out really good. Spray in the cleaner till it runs clear. See what you have at that point.

Thinking about it, you may want to also check the line running from the purge valve to the intake manifold. It is possible that that line has gotten damaged and that is what is causing your problems. You will want to also remove the line from the intake manifold to see if you have a good seal there (plug the hole in the intake manifold with some duct tape, start the car after clearing the codes and see if you still have the P0171/174 codes). If those go away, then you know your problem lies with the vacuum line to the purge valve or there is an issue with the purge valve.

 

Hey guys I've been busy lately but finally went to O'Reillys today to get those o-rings and do the replacement, and of course they didn't have them. I guess I have to order them from Jaguar or motorcarsltd.com or something, so i was wondering what site you guys suggest, specifically Thermo if you ever had to deal with shipping Jaguar parts to Hawaii. In addition, I figured while I'm in there I would do some other maintenance like replace the spark plugs and the intake manifold gasket. The car has 94000 miles and probably hasn't had anything done yet judging by the condition it's in. Is there anything else I should do, and do I need any lubricants or sealants or something to do all this?

 

ekuest, unfortunately, having been in your spot (not with the Jag, but my Ford Expedition), you have 2 options as I see them. The slower option is to simply call up a place in the continental US and wait for it to get shipped to you. You can possibly speed things up a little bit to pay for expedited shipping. But, now you are costing yourself a lot more to save a few days.

The other option is to simply get a ride to the auto parts store with the o-ring in hand and see if the guy behind the parts counter can match up an o-ring they have in the store to what you need. I know one of the members just posted a pic of the o-ring he found and it had a part number on it (quick look didn't allow me to find it).

As for other stuff to do while in there, that is up to you. Now, you are close to the 100K mile mark, so, this would be a good time to update the plugs. These are available at any parts store and should be sitting on the shelf. Big thing here is to keep it simple. We have found that the multiple spark plugs (ie, Bosch +4's, Splitfires, etc) do nothing for our cars and if anything create more problems than they could even think about fixing. Stick with a double platinum plug by a known manufacturer (NGK, Motorcraft, etc). You may want to also consider replacing the upper and lower intake seals since you are in that far. The trick with these is to get the parts for an 02 Lincoln LS 3.0L motor. They are the same parts. The store should have those on the shelf.

 

That's fine, I don't mind the wait as long as I don't have to spend $20 on shipping for $5 worth of parts. I guess the o-rings are the only thing I need to order online then? I read about doing the plugs and seals on another thread, nothing else you'd recommend?

 

ekuest, since you are into the intake, might as well make sure that the air filter is good. After that, get yourself a can of MAF sensor cleaner and a can of throttle body cleaner (not carb cleaner). Use both of those to make sure that the car is back in tip top shape. Since the intake will be off, it will be the prime time to do the throttle body cleaning (open the silver disk, aka butterfly valve, and anything that you see brown, attempt to wash it away with the throttle body cleaner, pay special attention to the edge of the disk where it comes very close to the outside diameter of the throttle body body).

Some might even say to go a step further and remove the fuel injectors and clean those. But, I have found that you can do a fairly decent job by simply going from say Shell gas to Sunoco gas (ie, switch major brands). This works on the principle that they all use a different detergent package in their gasolines and by switching brands, you are getting different chemicals flowing through your fuel system and it will get rid of what the other brand doesn't cover. if you remove the fuel injectors, there are videos on youtube of how you clean them. Fairly easy to do, just takes a little bit of ingenuity.