Bamber trailed teammate Nick Tandy after the first runs during the wet qualifying session by less than two tenths of a second.

Hartley went quicker than Andre Lotterer to jump ahead of the #1 Porsche 919 Hybrid, before the German improved his time to claim back the top spot.

The New Zealander, who leads the WEC standings with Bamber and Timo Bernhard, responded to propel the #2 car back to the top of the timesheets.

Bamber and Hartley ended up with two-lap average for 1m35.160s, which put them just 0.071s up on Tandy and Lotterer's 1m35.231s.

Toyota was less than two tenths of a second behind with the #8 TS050 Hybrid qualified by Kazuki Nakajima and Sebastien Buemi.

Nakajima had trailed Tandy's session-best of 1m35.068s by almost exactly two tenths, before Buemi whittled his time down to a 1m34.441s to run the Porsches close.

Jose Maria Lopez and Kamui Kobayashi were over a second back on their teammates in fourth position in the #7 Toyota.

Hartley said: "That was seriously close between the two Porsches, and Buemi at the end there was on fast lap.

"The Toyota look strong on the long runs, so we are expecting a close race tomorrow."

Rebellion quickest in LMP2, Porsche in GTE

Nelson Piquet Jr and David Heinemeier Hansson led an LMP2 one-two for the Rebellion team.

Piquet Jr headed teammate Bruno Senna by three tenths after the first runs, and then Heinemeier Hansson had more than a second in hand over Julien Canal in the sister Oreca-Gibson 07.

That gave the #13 car a two-lap average of 1m44.196s, seven tenths clear of their team-mates.

Ho-Pin Tung and Thomas Laurent were less than a tenth back in third aboard the lead Jackie Chan DC Racing Oreca.

Porsche took the pole in GTE Pro, Richard Lietz and Frederic Makowiecki taking the top spot with a 1m47.533s average.

That put them four tenths up on the Ganassi Ford GT driven by Andy Priaulx and Harry Tincknell.

The Clearwater Ferrari team took its first GTE Am pole with Matt Griffin and Weng Sun Mok.

Prototype qualifying:

Pos.	#	Drivers	Car	Class	Time	Gap
1	2	Timo Bernhard   Brendon Hartley   Earl Bamber	Porsche 919 Hybrid	LMP1	1'35.160
2	1	Andre Lotterer   Neel Jani   Nick Tandy	Porsche 919 Hybrid	LMP1	1'35.231	0.071
3	8	Anthony Davidson   Kazuki Nakajima   Sébastien Buemi	Toyota TS050 Hybrid	LMP1	1'35.355	0.195
4	7	Kamui Kobayashi   Mike Conway   Jose Maria Lopez	Toyota TS050 Hybrid	LMP1	1'36.630	1.470
5	13	Nelson Piquet Jr.   David Heinemeier Hansson   Mathias Beche	Oreca 07	LMP2	1'44.196	9.036
6	31	Bruno Senna   Julien Canal   Nicolas Prost	Oreca 07	LMP2	1'44.925	9.765
7	38	Oliver Jarvis   Ho-Pin Tung   Thomas Laurent	Oreca 07	LMP2	1'45.078	9.918
8	36	Nicolas Lapierre   Andre Negrao   Gustavo Menezes	Alpine A470	LMP2	1'45.927	10.767
9	37	David Cheng   Tristan Gommendy   Alex Brundle	Oreca 07	LMP2	1'46.109	10.949
10	26	Roman Rusinov   Pierre Thiriet   James Rossiter	Oreca 07	LMP2	1'46.205	11.045
11	25	Vitaly Petrov   Simon Trummer   Roberto Gonzalez	Oreca 07	LMP2	1'47.354	12.194
12	24	Jean-Eric Vergne   Ben Hanley   Matt Rao	Oreca 07	LMP2	1'47.411	12.251
13	28	François Perrodo   Emmanuel Collard   Matthieu Vaxiviere	Oreca 07	LMP2	1'47.989	12.829

GTE qualifying:

Pos.	#	Drivers	Car	Class	Time	Gap
1	91	Richard Lietz   Frédéric Makowiecki	Porsche 911 RSR	LMGTE PRO	1'47.577
2	67	Harry Tincknell   Andy Priaulx	Ford GT	LMGTE PRO	1'48.018	0.441
3	66	Stefan Mücke   Olivier Pla	Ford GT	LMGTE PRO	1'48.139	0.562
4	71	Sam Bird   Davide Rigon	Ferrari 488 GTE	LMGTE PRO	1'48.195	0.618
5	92	Michael Christensen   Kevin Estre	Porsche 911 RSR	LMGTE PRO	1'48.265	0.688
6	95	Marco Sorensen   Nicki Thiim	Aston Martin Vantage	LMGTE PRO	1'48.578	1.001
7	51	James Calado   Alessandro Pier Guidi	Ferrari 488 GTE	LMGTE PRO	1'48.702	1.125
8	97	Darren Turner   Jonathan Adam	Aston Martin Vantage	LMGTE PRO	1'49.125	1.548
9	61	Matt Griffin   Mok Weng Sun   Keita Sawa	Ferrari 488 GTE	LMGTE AM	1'49.408	1.831
10	77	Christian Ried   Matteo Cairoli   Marvin Dienst	Porsche 911 RSR (991)	LMGTE AM	1'49.734	2.157
11	98	Pedro Lamy   Paul Dalla Lana   Mathias Lauda	Aston Martin Vantage V8	LMGTE AM	1'49.784	2.207
12	86	Mike Hedlund   Ben Barker   Nick Foster Jr.	Porsche 911 RSR (991)	LMGTE AM	1'49.866	2.289
13	54	Francesco Castellacci   Miguel Molina   Thomas Flohr	Ferrari 488 GTE	LMGTE AM	1'50.797	3.220