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Trouble removing ABS Brake Sensor


mjac

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I am having considerable trouble removing this (very likely) original brake sensor. I found one in a Reatta in the boneyard, hoping it works better than mine. I've tried heating it, tapping it, putting rust remover on it, i bought a special wrench, and a deep 36 socket (machined to fit around this sensor). It doesn't budge. Please don't tell me I have to turn it to the right to remove it.....i may pull my hair out! 🤪  Any ideas on how to remove this sensor? 

brake sensor

 

 

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Welcome to the forum!

 

Your photo is pretty small but it appears you are trying to remove the pressure switch. I don't know why it would be so hard to remove. Seems like you are doing it the right way. Keep applying penetrating oil for a few days and see if that helps.

 

It does have standard right hand threads. Not left handed threads. 

 

I will give  you some good advice. When you are trying to turn the pressure switch with that much force you need to hold the pump assembly with some large channel locks or something similar to keep from putting stress on it. The pump assembly is bolted to the master cylinder with just one bolt.  You don't want to break that bolt by twisting too hard on the pressure switch.

 

 

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Thank you Ronnie! I did manage to get it loose. It took a long 36 socket with an impact wrench, but it came loose. Unfortunately, the junkyard sensor failed as well. It did at least tell me accurately that the brake fluid was low (the contents of the accumulator sprays out when you remove the sensor). Added fluid, but

the ABS Light is still lit. 

 

 

 

 

reattaengine.thumb.jpg.895c207d2e6d085cdbb29bccae2d075e.jpg Reattaafterbrakesensorreplaced.thumb.jpg.baffe20d8910d5db2d456d63b641d089.jpgReattainterior.jpg.18c96e2c8e6dd8cc4983bc5328d38d13.jpgRita88.thumb.jpg.ba31cf78294a29e986f11494c90563b2.jpg

Edited by mjac
photo too small
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Pull the codes for the ABS and see what you get' Post what you find here and we might be able to help. Instructions for doing that are in the menu at the top of the page. The part you are working on is  the power brake system which is separate from the system that turns on the ABS light.

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The pressure switches rarely fail to work properly unless fluid leaks into the electrical connection so save the one you removed. The pressure sensor does three things, all related to system pressure. It controls when the pump starts and stops, and it will also illuminate the red light if pressure is low and related to that, it tells the ABS system the pressure is low which illuminates the amber light. If the amber won’t go off but the red light does, it isn’t the pressure switch causing that, it is likely a wheel speed sensor. Pull codes as Ronnie suggested

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Should have grabbed the pump and motor. I have gone through more of them then I have the brake sensor.

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Okay, I'm back at it this morning on my 88. Thank you for the ABS control module info. Unfortunately, when I jumpered the A&G terminals in the ABS Control module, I got no flashes at all. NONE. The ABS light stayed solid after several attempts. I'm wondering if I have a malfunctioning ALDL?     

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Check the ABS fuse and relay. You can swap the relays on the firewall as a test to see if the relay is the problem. All three relays are the same. Then try again to check ABS codes.

 

88-89_relays_firewall.jpg

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So I swapped the ABS Main Relay with the Brake Pump Relay. ABS Codes were 22 then 23 (2nd jumper with the ignition on).  I see in the ABS Code chart a 22 and 23 are Left Front Inlet valve, and Left front outlet valve. Wondering how easy these are to get.  Both relays are now working....dirt/time/position/contact surface or whatever was the cause of relay failure, both relays are now working.  Are the valves inside the main ABS, or external at the wheel. I'm not a mechanic so forgive my dumb question if this is common knowledge. If they are internal to the ABS I might be able to test with a multimeter if I had a pinout of the main ABS connector. Thank you for your patience and knowledge. I'm a retired computer technician, so I realize how valuable this information is. 

Edited by mjac
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I found a photo of the solenoid valves for the Teves II Mark 2 ABS System. This photo is from a 1990 Jaguar. I may try removing the ABS unit and check the connections to the solenoids. I could solder a broken one if I see one. I think Front valves are on the top, Rear valves on the bottom. This might be enough to fix the issue. If not, it looks like I will need a replacement ABS unit. Has anyone had success with this? 

 

ABSvalvebody.thumb.jpg.b84309ceb08102894875a0973e6a2d4f.jpg

 

 

TevesinternalABSvalves.jpg.18f8818092a9fe63459c95a81bebbdd8.jpg

Edited by mjac
added a photo
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No experience taking one apart and I believe you venturing into unknown territory. As far as I know, the valve module itself is replaceable but no idea of a source except used takeoffs. Best of luck and I am very interested in what you find.

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7 hours ago, mjac said:

Are the valves inside the main ABS, or external at the wheel. I'm not a mechanic so forgive my dumb question if this is common knowledge. If they are internal to the ABS I might be able to test with a multimeter if I had a pinout of the main ABS connector.

Before you do a teardown let me see if I can find a pinout so you can do some testing. I'm pretty sure there is a breakout box for that purpose. If you are talking about disconnecting brake lines you may be risking problems that can be avoided by doing some testing. 

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This is what I could find that might allow you to test the valves. Is this what you need? There are about a dozen pages in the service manual for troubleshooting ABS codes 22 and 23. You really need a manual to do it right.

 

ABS vlave circuit_.jpeg

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Nice find on that pinout diagram, Ronnie! Thank you. I removed the valve body cover and had a peek inside. It looks a lot like the pic below of the Teves Mark 2 valve body from a Jaguar. With the Ohm Meter, I checked the continuity of each of the connections. They had resistance between 6.4 - 7.0 Ohms. Except for one, which read 4.8 Ohms, but I found no open circuit, thankfully. Those ribbon cables look pretty flimsy though. If I were to take out the valve body, I would replace them with wire.  It was getting late, so I didn't remove the valve body which would require a lot more work, especially since there didn't appear to be any broken connections. There wasn't a gasket or seal of any kind on the cover, which I thought was kinda odd. Anyway, the valves looked good (no rust) so apparently, water getting in there isn't an issue. I pressurized the accumulator by pumping the brake pedal (engine off) till I felt some pushback. I took it for a quick spin, and to my delight, the ABS light which has plagued me since I bought the car, was OFF. Yippee! Not sure what happened. I may have reseated a crummy connection when I was poking around the ribbon cables. Anyway, we'll see how long it lasts. Thank you for your help. I learned a great deal more about my Reatta. My next repair will be to replace the nearly disintegrated vac hoses on the speed control. The computer is prompting me to fix it far too often. 

 

 

Valvebody1990JaguarXJS.thumb.jpg.53302b46968db9f40c0beae4659295d7.jpg   

 

ReattaABSValveCircuitpinout.jpg.8f70bbecd51a05796d380e9f984e895a.jpg

 

 

Edited by mjac
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That's good news. I'll bet the problem was a bad connection. The ABS valves seldom give trouble.

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